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https://github.com/RGBCube/serenity
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LibVideo: Read Matroska lazily so that large files can start quickly
The Demuxer class was changed to return errors for more functions so that all of the underlying reading can be done lazily. Other than that, the demuxer interface is unchanged, and only the underlying reader was modified. The MatroskaDocument class is no more, and MatroskaReader's getter functions replace it. Every MatroskaReader getter beyond the Segment element's position is parsed lazily from the file as needed. This means that all getter functions can return DecoderErrors which must be handled by callers.
This commit is contained in:
Zaggy1024
Andreas Kling
parent
f4c476b26f
commit
393cfdd5c5
11 changed files with 576 additions and 310 deletions
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@ -7,6 +7,7 @@
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#include <AK/Function.h>
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#include <AK/Optional.h>
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#include <AK/Time.h>
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#include <AK/Utf8View.h>
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#include <LibCore/MappedFile.h>
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@ -16,10 +17,18 @@ namespace Video::Matroska {
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#define TRY_READ(expression) DECODER_TRY(DecoderErrorCategory::Corrupted, expression)
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// Elements IDs and types are listed at this URL:
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// https://www.matroska.org/technical/elements.html
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constexpr u32 EBML_MASTER_ELEMENT_ID = 0x1A45DFA3;
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constexpr u32 SEGMENT_ELEMENT_ID = 0x18538067;
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constexpr u32 DOCTYPE_ELEMENT_ID = 0x4282;
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constexpr u32 DOCTYPE_VERSION_ELEMENT_ID = 0x4287;
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constexpr u32 SEEK_HEAD_ELEMENT_ID = 0x114D9B74;
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constexpr u32 SEEK_ELEMENT_ID = 0x4DBB;
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constexpr u32 SEEK_ID_ELEMENT_ID = 0x53AB;
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constexpr u32 SEEK_POSITION_ELEMENT_ID = 0x53AC;
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constexpr u32 SEGMENT_INFORMATION_ELEMENT_ID = 0x1549A966;
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constexpr u32 TRACK_ELEMENT_ID = 0x1654AE6B;
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constexpr u32 CLUSTER_ELEMENT_ID = 0x1F43B675;
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@ -55,19 +64,22 @@ constexpr u32 BIT_DEPTH_ID = 0x6264;
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constexpr u32 SIMPLE_BLOCK_ID = 0xA3;
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constexpr u32 TIMESTAMP_ID = 0xE7;
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DecoderErrorOr<NonnullOwnPtr<MatroskaDocument>> Reader::parse_matroska_from_file(StringView path)
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DecoderErrorOr<Reader> Reader::from_file(StringView path)
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{
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auto mapped_file = DECODER_TRY(DecoderErrorCategory::IO, Core::MappedFile::map(path));
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return parse_matroska_from_data(mapped_file->bytes());
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auto reader = TRY(from_data(mapped_file->bytes()));
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reader.m_mapped_file = mapped_file;
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return reader;
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}
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DecoderErrorOr<NonnullOwnPtr<MatroskaDocument>> Reader::parse_matroska_from_data(ReadonlyBytes data)
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DecoderErrorOr<Reader> Reader::from_data(ReadonlyBytes data)
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{
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Reader reader(data);
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return reader.parse();
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TRY(reader.parse_initial_data());
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return reader;
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}
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static DecoderErrorOr<void> parse_master_element(Streamer& streamer, [[maybe_unused]] StringView element_name, Function<DecoderErrorOr<void>(u64)> element_consumer)
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static DecoderErrorOr<void> parse_master_element(Streamer& streamer, [[maybe_unused]] StringView element_name, Function<DecoderErrorOr<IterationDecision>(u64, size_t)> element_consumer)
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{
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auto element_data_size = TRY_READ(streamer.read_variable_size_integer());
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dbgln_if(MATROSKA_DEBUG, "{} has {} octets of data.", element_name, element_data_size);
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@ -76,9 +88,15 @@ static DecoderErrorOr<void> parse_master_element(Streamer& streamer, [[maybe_unu
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while (streamer.octets_read() < element_data_size) {
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dbgln_if(MATROSKA_TRACE_DEBUG, "====== Reading element ======");
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auto element_id = TRY_READ(streamer.read_variable_size_integer(false));
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dbgln_if(MATROSKA_TRACE_DEBUG, "{:s} element ID is {:#010x}\n", element_name, element_id);
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auto element_position = streamer.position();
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dbgln_if(MATROSKA_TRACE_DEBUG, "{:s} element ID is {:#010x}", element_name, element_id);
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auto result = element_consumer(element_id, element_position);
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if (result.is_error())
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return DecoderError::format(result.error().category(), "{} -> {}", element_name, result.error().description());
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if (result.release_value() == IterationDecision::Break)
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break;
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TRY(element_consumer(element_id));
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dbgln_if(MATROSKA_TRACE_DEBUG, "Read {} octets of the {} so far.", streamer.octets_read(), element_name);
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}
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streamer.pop_octets_read();
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@ -89,7 +107,7 @@ static DecoderErrorOr<void> parse_master_element(Streamer& streamer, [[maybe_unu
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static DecoderErrorOr<EBMLHeader> parse_ebml_header(Streamer& streamer)
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{
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EBMLHeader header;
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TRY(parse_master_element(streamer, "Header"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
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TRY(parse_master_element(streamer, "Header"sv, [&](u64 element_id, size_t) -> DecoderErrorOr<IterationDecision> {
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switch (element_id) {
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case DOCTYPE_ELEMENT_ID:
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header.doc_type = TRY_READ(streamer.read_string());
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@ -103,93 +121,198 @@ static DecoderErrorOr<EBMLHeader> parse_ebml_header(Streamer& streamer)
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TRY_READ(streamer.read_unknown_element());
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}
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return {};
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return IterationDecision::Continue;
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}));
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return header;
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}
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static DecoderErrorOr<NonnullOwnPtr<SegmentInformation>> parse_information(Streamer& streamer);
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static DecoderErrorOr<void> parse_tracks(Streamer& streamer, MatroskaDocument& matroska_document);
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static DecoderErrorOr<NonnullOwnPtr<Cluster>> parse_cluster(Streamer& streamer);
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static DecoderErrorOr<void> parse_segment_elements(Streamer& streamer, MatroskaDocument& matroska_document)
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DecoderErrorOr<void> Reader::parse_initial_data()
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{
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dbgln_if(MATROSKA_DEBUG, "Parsing segment elements");
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return parse_master_element(streamer, "Segment"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
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switch (element_id) {
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case SEGMENT_INFORMATION_ELEMENT_ID:
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matroska_document.set_segment_information(TRY(parse_information(streamer)));
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break;
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case TRACK_ELEMENT_ID:
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TRY(parse_tracks(streamer, matroska_document));
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break;
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case CLUSTER_ELEMENT_ID:
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matroska_document.clusters().append(TRY(parse_cluster(streamer)));
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break;
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default:
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TRY_READ(streamer.read_unknown_element());
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}
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return {};
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});
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}
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DecoderErrorOr<NonnullOwnPtr<MatroskaDocument>> Reader::parse()
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{
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auto first_element_id = TRY_READ(m_streamer.read_variable_size_integer(false));
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Streamer streamer { m_data };
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auto first_element_id = TRY_READ(streamer.read_variable_size_integer(false));
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dbgln_if(MATROSKA_TRACE_DEBUG, "First element ID is {:#010x}\n", first_element_id);
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if (first_element_id != EBML_MASTER_ELEMENT_ID)
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return DecoderError::corrupted("First element was not an EBML header"sv);
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auto header = TRY(parse_ebml_header(m_streamer));
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m_header = TRY(parse_ebml_header(streamer));
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dbgln_if(MATROSKA_DEBUG, "Parsed EBML header");
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auto root_element_id = TRY_READ(m_streamer.read_variable_size_integer(false));
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auto root_element_id = TRY_READ(streamer.read_variable_size_integer(false));
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if (root_element_id != SEGMENT_ELEMENT_ID)
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return DecoderError::corrupted("Second element was not a segment element"sv);
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auto matroska_document = make<MatroskaDocument>(header);
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TRY(parse_segment_elements(m_streamer, *matroska_document));
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return matroska_document;
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m_segment_contents_size = TRY_READ(streamer.read_variable_size_integer());
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m_segment_contents_position = streamer.position();
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dbgln_if(true, "Segment is at {} with size {}, available size is {}", m_segment_contents_position, m_segment_contents_size, m_data.size() - m_segment_contents_position);
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m_segment_contents_size = min(m_segment_contents_size, m_data.size() - m_segment_contents_position);
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return {};
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}
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static DecoderErrorOr<NonnullOwnPtr<SegmentInformation>> parse_information(Streamer& streamer)
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static DecoderErrorOr<void> parse_seek_head(Streamer& streamer, size_t base_position, HashMap<u32, size_t>& table)
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{
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auto segment_information = make<SegmentInformation>();
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TRY(parse_master_element(streamer, "Segment Information"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
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return parse_master_element(streamer, "SeekHead"sv, [&](u64 seek_head_child_id, size_t) -> DecoderErrorOr<IterationDecision> {
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if (seek_head_child_id == SEEK_ELEMENT_ID) {
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Optional<u64> seek_id;
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Optional<u64> seek_position;
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TRY(parse_master_element(streamer, "Seek"sv, [&](u64 seek_entry_child_id, size_t) -> DecoderErrorOr<IterationDecision> {
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switch (seek_entry_child_id) {
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case SEEK_ID_ELEMENT_ID:
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seek_id = TRY_READ(streamer.read_u64());
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dbgln_if(MATROSKA_TRACE_DEBUG, "Read Seek Element ID value {:#010x}", seek_id.value());
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break;
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case SEEK_POSITION_ELEMENT_ID:
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seek_position = TRY_READ(streamer.read_u64());
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dbgln_if(MATROSKA_TRACE_DEBUG, "Read Seek Position value {}", seek_position.value());
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break;
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default:
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TRY_READ(streamer.read_unknown_element());
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}
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return IterationDecision::Continue;
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}));
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if (!seek_id.has_value())
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return DecoderError::corrupted("Seek entry is missing the element ID"sv);
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if (!seek_position.has_value())
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return DecoderError::corrupted("Seek entry is missing the seeking position"sv);
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if (seek_id.value() > NumericLimits<u32>::max())
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return DecoderError::corrupted("Seek entry's element ID is too large"sv);
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dbgln_if(MATROSKA_TRACE_DEBUG, "Seek entry found with ID {:#010x} and position {} offset from SeekHead at {}", seek_id.value(), seek_position.value(), base_position);
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// FIXME: SeekHead can reference another SeekHead, we should recursively parse all SeekHeads.
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if (table.contains(seek_id.value())) {
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dbgln_if(MATROSKA_DEBUG, "Warning: Duplicate seek entry with ID {:#010x} at position {}", seek_id.value(), seek_position.value());
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return IterationDecision::Continue;
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}
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DECODER_TRY_ALLOC(table.try_set(seek_id.release_value(), base_position + seek_position.release_value()));
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} else {
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dbgln_if(MATROSKA_TRACE_DEBUG, "Unknown SeekHead child element ID {:#010x}", seek_head_child_id);
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}
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return IterationDecision::Continue;
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});
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}
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DecoderErrorOr<Optional<size_t>> Reader::find_first_top_level_element_with_id([[maybe_unused]] StringView element_name, u32 element_id)
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{
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dbgln_if(MATROSKA_DEBUG, "====== Finding element {} with ID {:#010x} ======", element_name, element_id);
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if (m_seek_entries.contains(element_id)) {
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dbgln_if(MATROSKA_TRACE_DEBUG, "Cache hit!");
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return m_seek_entries.get(element_id).release_value();
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}
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Streamer streamer { m_data };
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if (m_last_top_level_element_position != 0)
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TRY_READ(streamer.seek_to_position(m_last_top_level_element_position));
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else
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TRY_READ(streamer.seek_to_position(m_segment_contents_position));
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Optional<size_t> position;
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while (streamer.position() < m_segment_contents_position + m_segment_contents_size) {
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auto found_element_id = TRY_READ(streamer.read_variable_size_integer(false));
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auto found_element_position = streamer.position();
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dbgln_if(MATROSKA_TRACE_DEBUG, "Found element ID {:#010x} with position {}.", found_element_id, found_element_position);
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if (found_element_id == SEEK_HEAD_ELEMENT_ID) {
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dbgln_if(MATROSKA_TRACE_DEBUG, "Found SeekHead, parsing it into the lookup table.");
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m_seek_entries.clear();
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TRY(parse_seek_head(streamer, found_element_position, m_seek_entries));
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m_last_top_level_element_position = 0;
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if (m_seek_entries.contains(element_id)) {
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dbgln_if(MATROSKA_TRACE_DEBUG, "SeekHead hit!");
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position = m_seek_entries.get(element_id).release_value();
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break;
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}
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continue;
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}
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auto result = streamer.read_unknown_element();
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if (result.is_error())
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return DecoderError::format(DecoderErrorCategory::Corrupted, "While seeking to {}: {}", element_name, result.release_error().string_literal());
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m_last_top_level_element_position = streamer.position();
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DECODER_TRY_ALLOC(m_seek_entries.try_set(found_element_id, found_element_position));
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if (found_element_id == element_id) {
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position = found_element_position;
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break;
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}
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dbgln_if(MATROSKA_TRACE_DEBUG, "Skipped to position {}.", m_last_top_level_element_position);
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}
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return position;
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}
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static DecoderErrorOr<SegmentInformation> parse_information(Streamer& streamer)
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{
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SegmentInformation segment_information;
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TRY(parse_master_element(streamer, "Segment Information"sv, [&](u64 element_id, size_t) -> DecoderErrorOr<IterationDecision> {
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switch (element_id) {
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case TIMESTAMP_SCALE_ID:
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segment_information->set_timestamp_scale(TRY_READ(streamer.read_u64()));
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dbgln_if(MATROSKA_DEBUG, "Read TimestampScale attribute: {}", segment_information->timestamp_scale());
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segment_information.set_timestamp_scale(TRY_READ(streamer.read_u64()));
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dbgln_if(MATROSKA_DEBUG, "Read TimestampScale attribute: {}", segment_information.timestamp_scale());
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break;
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case MUXING_APP_ID:
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segment_information->set_muxing_app(TRY_READ(streamer.read_string()));
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dbgln_if(MATROSKA_DEBUG, "Read MuxingApp attribute: {}", segment_information->muxing_app().as_string());
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segment_information.set_muxing_app(TRY_READ(streamer.read_string()));
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dbgln_if(MATROSKA_DEBUG, "Read MuxingApp attribute: {}", segment_information.muxing_app().as_string());
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break;
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case WRITING_APP_ID:
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segment_information->set_writing_app(TRY_READ(streamer.read_string()));
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dbgln_if(MATROSKA_DEBUG, "Read WritingApp attribute: {}", segment_information->writing_app().as_string());
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segment_information.set_writing_app(TRY_READ(streamer.read_string()));
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dbgln_if(MATROSKA_DEBUG, "Read WritingApp attribute: {}", segment_information.writing_app().as_string());
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break;
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case DURATION_ID:
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segment_information->set_duration(TRY_READ(streamer.read_float()));
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dbgln_if(MATROSKA_DEBUG, "Read Duration attribute: {}", segment_information->duration().value());
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segment_information.set_duration(TRY_READ(streamer.read_float()));
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dbgln_if(MATROSKA_DEBUG, "Read Duration attribute: {}", segment_information.duration().value());
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break;
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default:
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TRY_READ(streamer.read_unknown_element());
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}
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return {};
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return IterationDecision::Continue;
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}));
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return segment_information;
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}
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DecoderErrorOr<SegmentInformation> Reader::segment_information()
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{
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if (m_segment_information.has_value())
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return m_segment_information.value();
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auto position = TRY(find_first_top_level_element_with_id("Segment Information"sv, SEGMENT_INFORMATION_ELEMENT_ID));
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if (!position.has_value())
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return DecoderError::corrupted("No Segment Information element found"sv);
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Streamer streamer { m_data };
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TRY_READ(streamer.seek_to_position(position.release_value()));
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m_segment_information = TRY(parse_information(streamer));
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return m_segment_information.value();
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}
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DecoderErrorOr<void> Reader::ensure_tracks_are_parsed()
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{
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if (!m_tracks.is_empty())
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return {};
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auto position = TRY(find_first_top_level_element_with_id("Tracks"sv, TRACK_ELEMENT_ID));
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if (!position.has_value())
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return DecoderError::corrupted("No Tracks element found"sv);
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Streamer streamer { m_data };
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TRY_READ(streamer.seek_to_position(position.release_value()));
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TRY(parse_tracks(streamer));
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return {};
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}
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static DecoderErrorOr<TrackEntry::ColorFormat> parse_video_color_information(Streamer& streamer)
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{
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TrackEntry::ColorFormat color_format {};
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TRY(parse_master_element(streamer, "Colour"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
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TRY(parse_master_element(streamer, "Colour"sv, [&](u64 element_id, size_t) -> DecoderErrorOr<IterationDecision> {
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switch (element_id) {
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case PRIMARIES_ID:
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color_format.color_primaries = static_cast<ColorPrimaries>(TRY_READ(streamer.read_u64()));
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@ -211,7 +334,7 @@ static DecoderErrorOr<TrackEntry::ColorFormat> parse_video_color_information(Str
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TRY_READ(streamer.read_unknown_element());
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}
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return {};
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return IterationDecision::Continue;
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}));
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return color_format;
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@ -221,7 +344,7 @@ static DecoderErrorOr<TrackEntry::VideoTrack> parse_video_track_information(Stre
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{
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TrackEntry::VideoTrack video_track {};
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TRY(parse_master_element(streamer, "VideoTrack"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
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TRY(parse_master_element(streamer, "VideoTrack"sv, [&](u64 element_id, size_t) -> DecoderErrorOr<IterationDecision> {
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switch (element_id) {
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case PIXEL_WIDTH_ID:
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video_track.pixel_width = TRY_READ(streamer.read_u64());
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@ -238,7 +361,7 @@ static DecoderErrorOr<TrackEntry::VideoTrack> parse_video_track_information(Stre
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TRY_READ(streamer.read_unknown_element());
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}
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return {};
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return IterationDecision::Continue;
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}));
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return video_track;
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@ -248,7 +371,7 @@ static DecoderErrorOr<TrackEntry::AudioTrack> parse_audio_track_information(Stre
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{
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TrackEntry::AudioTrack audio_track {};
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TRY(parse_master_element(streamer, "AudioTrack"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
|
||||
TRY(parse_master_element(streamer, "AudioTrack"sv, [&](u64 element_id, size_t) -> DecoderErrorOr<IterationDecision> {
|
||||
switch (element_id) {
|
||||
case CHANNELS_ID:
|
||||
audio_track.channels = TRY_READ(streamer.read_u64());
|
||||
|
|
@ -262,114 +385,163 @@ static DecoderErrorOr<TrackEntry::AudioTrack> parse_audio_track_information(Stre
|
|||
TRY_READ(streamer.read_unknown_element());
|
||||
}
|
||||
|
||||
return {};
|
||||
return IterationDecision::Continue;
|
||||
}));
|
||||
|
||||
return audio_track;
|
||||
}
|
||||
|
||||
static DecoderErrorOr<NonnullOwnPtr<TrackEntry>> parse_track_entry(Streamer& streamer)
|
||||
static DecoderErrorOr<TrackEntry> parse_track_entry(Streamer& streamer)
|
||||
{
|
||||
auto track_entry = make<TrackEntry>();
|
||||
TRY(parse_master_element(streamer, "Track"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
|
||||
TrackEntry track_entry;
|
||||
TRY(parse_master_element(streamer, "Track"sv, [&](u64 element_id, size_t) -> DecoderErrorOr<IterationDecision> {
|
||||
switch (element_id) {
|
||||
case TRACK_NUMBER_ID:
|
||||
track_entry->set_track_number(TRY_READ(streamer.read_u64()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read TrackNumber attribute: {}", track_entry->track_number());
|
||||
track_entry.set_track_number(TRY_READ(streamer.read_u64()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read TrackNumber attribute: {}", track_entry.track_number());
|
||||
break;
|
||||
case TRACK_UID_ID:
|
||||
track_entry->set_track_uid(TRY_READ(streamer.read_u64()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read TrackUID attribute: {}", track_entry->track_uid());
|
||||
track_entry.set_track_uid(TRY_READ(streamer.read_u64()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read TrackUID attribute: {}", track_entry.track_uid());
|
||||
break;
|
||||
case TRACK_TYPE_ID:
|
||||
track_entry->set_track_type(static_cast<TrackEntry::TrackType>(TRY_READ(streamer.read_u64())));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read TrackType attribute: {}", track_entry->track_type());
|
||||
track_entry.set_track_type(static_cast<TrackEntry::TrackType>(TRY_READ(streamer.read_u64())));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read TrackType attribute: {}", to_underlying(track_entry.track_type()));
|
||||
break;
|
||||
case TRACK_LANGUAGE_ID:
|
||||
track_entry->set_language(TRY_READ(streamer.read_string()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read Track's Language attribute: {}", track_entry->language());
|
||||
track_entry.set_language(TRY_READ(streamer.read_string()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read Track's Language attribute: {}", track_entry.language());
|
||||
break;
|
||||
case TRACK_CODEC_ID:
|
||||
track_entry->set_codec_id(TRY_READ(streamer.read_string()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read Track's CodecID attribute: {}", track_entry->codec_id());
|
||||
track_entry.set_codec_id(TRY_READ(streamer.read_string()));
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Read Track's CodecID attribute: {}", track_entry.codec_id());
|
||||
break;
|
||||
case TRACK_VIDEO_ID:
|
||||
track_entry->set_video_track(TRY(parse_video_track_information(streamer)));
|
||||
track_entry.set_video_track(TRY(parse_video_track_information(streamer)));
|
||||
break;
|
||||
case TRACK_AUDIO_ID:
|
||||
track_entry->set_audio_track(TRY(parse_audio_track_information(streamer)));
|
||||
track_entry.set_audio_track(TRY(parse_audio_track_information(streamer)));
|
||||
break;
|
||||
default:
|
||||
TRY_READ(streamer.read_unknown_element());
|
||||
}
|
||||
|
||||
return {};
|
||||
return IterationDecision::Continue;
|
||||
}));
|
||||
|
||||
return track_entry;
|
||||
}
|
||||
|
||||
static DecoderErrorOr<void> parse_tracks(Streamer& streamer, MatroskaDocument& matroska_document)
|
||||
DecoderErrorOr<void> Reader::parse_tracks(Streamer& streamer)
|
||||
{
|
||||
return parse_master_element(streamer, "Tracks"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
|
||||
return parse_master_element(streamer, "Tracks"sv, [&](u64 element_id, size_t) -> DecoderErrorOr<IterationDecision> {
|
||||
if (element_id == TRACK_ENTRY_ID) {
|
||||
dbgln_if(MATROSKA_DEBUG, "Parsing track");
|
||||
auto track_entry = TRY(parse_track_entry(streamer));
|
||||
auto track_number = track_entry->track_number();
|
||||
dbgln_if(MATROSKA_DEBUG, "Adding track {} to document", track_number);
|
||||
matroska_document.add_track(track_number, track_entry.release_nonnull<TrackEntry>());
|
||||
dbgln_if(MATROSKA_DEBUG, "Parsed track {}", track_entry.track_number());
|
||||
DECODER_TRY_ALLOC(m_tracks.try_set(track_entry.track_number(), track_entry));
|
||||
} else {
|
||||
TRY_READ(streamer.read_unknown_element());
|
||||
}
|
||||
|
||||
return {};
|
||||
return IterationDecision::Continue;
|
||||
});
|
||||
}
|
||||
|
||||
static DecoderErrorOr<NonnullOwnPtr<Block>> parse_simple_block(Streamer& streamer);
|
||||
|
||||
static DecoderErrorOr<NonnullOwnPtr<Cluster>> parse_cluster(Streamer& streamer)
|
||||
DecoderErrorOr<void> Reader::for_each_track(TrackEntryCallback callback)
|
||||
{
|
||||
auto cluster = make<Cluster>();
|
||||
TRY(ensure_tracks_are_parsed());
|
||||
for (auto const& track_entry : m_tracks) {
|
||||
auto decision = TRY(callback(track_entry.value));
|
||||
if (decision == IterationDecision::Break)
|
||||
break;
|
||||
}
|
||||
return {};
|
||||
}
|
||||
|
||||
DecoderErrorOr<void> Reader::for_each_track_of_type(TrackEntry::TrackType type, TrackEntryCallback callback)
|
||||
{
|
||||
return for_each_track([&](TrackEntry const& track_entry) -> DecoderErrorOr<IterationDecision> {
|
||||
if (track_entry.track_type() != type)
|
||||
return IterationDecision::Continue;
|
||||
return callback(track_entry);
|
||||
});
|
||||
}
|
||||
|
||||
DecoderErrorOr<TrackEntry> Reader::track_for_track_number(u64 track_number)
|
||||
{
|
||||
TRY(ensure_tracks_are_parsed());
|
||||
auto optional_track_entry = m_tracks.get(track_number);
|
||||
if (!optional_track_entry.has_value())
|
||||
return DecoderError::format(DecoderErrorCategory::Invalid, "No track found with number {}", track_number);
|
||||
return optional_track_entry.release_value();
|
||||
}
|
||||
|
||||
DecoderErrorOr<size_t> Reader::track_count()
|
||||
{
|
||||
TRY(ensure_tracks_are_parsed());
|
||||
return m_tracks.size();
|
||||
}
|
||||
|
||||
constexpr size_t get_element_id_size(u32 element_id)
|
||||
{
|
||||
return sizeof(element_id) - (count_leading_zeroes(element_id) / 8);
|
||||
}
|
||||
|
||||
static DecoderErrorOr<Cluster> parse_cluster(Streamer& streamer)
|
||||
{
|
||||
Optional<u64> timestamp;
|
||||
size_t first_element_position = 0;
|
||||
|
||||
TRY(parse_master_element(streamer, "Cluster"sv, [&](u64 element_id, size_t position) -> DecoderErrorOr<IterationDecision> {
|
||||
if (first_element_position == 0)
|
||||
first_element_position = position - get_element_id_size(element_id);
|
||||
|
||||
TRY(parse_master_element(streamer, "Cluster"sv, [&](u64 element_id) -> DecoderErrorOr<void> {
|
||||
switch (element_id) {
|
||||
case SIMPLE_BLOCK_ID:
|
||||
cluster->blocks().append(TRY(parse_simple_block(streamer)));
|
||||
break;
|
||||
case TIMESTAMP_ID:
|
||||
cluster->set_timestamp(TRY_READ(streamer.read_u64()));
|
||||
break;
|
||||
timestamp = TRY_READ(streamer.read_u64());
|
||||
return IterationDecision::Break;
|
||||
default:
|
||||
TRY_READ(streamer.read_unknown_element());
|
||||
}
|
||||
|
||||
return {};
|
||||
return IterationDecision::Continue;
|
||||
}));
|
||||
|
||||
if (!timestamp.has_value())
|
||||
return DecoderError::corrupted("Cluster was missing a timestamp"sv);
|
||||
if (first_element_position == 0)
|
||||
return DecoderError::corrupted("Cluster had no children"sv);
|
||||
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Seeking back to position {}", first_element_position);
|
||||
TRY_READ(streamer.seek_to_position(first_element_position));
|
||||
|
||||
Cluster cluster;
|
||||
cluster.set_timestamp(timestamp.release_value());
|
||||
return cluster;
|
||||
}
|
||||
|
||||
static DecoderErrorOr<NonnullOwnPtr<Block>> parse_simple_block(Streamer& streamer)
|
||||
static DecoderErrorOr<Block> parse_simple_block(Streamer& streamer)
|
||||
{
|
||||
auto block = make<Block>();
|
||||
Block block;
|
||||
|
||||
auto content_size = TRY_READ(streamer.read_variable_size_integer());
|
||||
|
||||
auto octets_read_before_track_number = streamer.octets_read();
|
||||
auto track_number = TRY_READ(streamer.read_variable_size_integer());
|
||||
block->set_track_number(track_number);
|
||||
auto position_before_track_number = streamer.position();
|
||||
block.set_track_number(TRY_READ(streamer.read_variable_size_integer()));
|
||||
|
||||
block->set_timestamp(TRY_READ(streamer.read_i16()));
|
||||
block.set_timestamp(TRY_READ(streamer.read_i16()));
|
||||
|
||||
auto flags = TRY_READ(streamer.read_octet());
|
||||
block->set_only_keyframes((flags & (1u << 7u)) != 0);
|
||||
block->set_invisible((flags & (1u << 3u)) != 0);
|
||||
block->set_lacing(static_cast<Block::Lacing>((flags & 0b110u) >> 1u));
|
||||
block->set_discardable((flags & 1u) != 0);
|
||||
block.set_only_keyframes((flags & (1u << 7u)) != 0);
|
||||
block.set_invisible((flags & (1u << 3u)) != 0);
|
||||
block.set_lacing(static_cast<Block::Lacing>((flags & 0b110u) >> 1u));
|
||||
block.set_discardable((flags & 1u) != 0);
|
||||
|
||||
auto total_frame_content_size = content_size - (streamer.octets_read() - octets_read_before_track_number);
|
||||
if (block->lacing() == Block::Lacing::EBML) {
|
||||
auto total_frame_content_size = content_size - (streamer.position() - position_before_track_number);
|
||||
|
||||
Vector<ReadonlyBytes> frames;
|
||||
|
||||
if (block.lacing() == Block::Lacing::EBML) {
|
||||
auto octets_read_before_frame_sizes = streamer.octets_read();
|
||||
auto frame_count = TRY_READ(streamer.read_octet()) + 1;
|
||||
Vector<u64> frame_sizes;
|
||||
|
|
@ -385,7 +557,7 @@ static DecoderErrorOr<NonnullOwnPtr<Block>> parse_simple_block(Streamer& streame
|
|||
for (int i = 0; i < frame_count - 2; i++) {
|
||||
auto frame_size_difference = TRY_READ(streamer.read_variable_size_signed_integer());
|
||||
u64 frame_size;
|
||||
// FIXME: x - (-y) == x + y??
|
||||
// FIXME: x - (-y) == x + y?
|
||||
if (frame_size_difference < 0)
|
||||
frame_size = previous_frame_size - (-frame_size_difference);
|
||||
else
|
||||
|
|
@ -399,30 +571,89 @@ static DecoderErrorOr<NonnullOwnPtr<Block>> parse_simple_block(Streamer& streame
|
|||
for (int i = 0; i < frame_count; i++) {
|
||||
// FIXME: ReadonlyBytes instead of copying the frame data?
|
||||
auto current_frame_size = frame_sizes.at(i);
|
||||
block->add_frame(DECODER_TRY_ALLOC(ByteBuffer::copy(streamer.data(), current_frame_size)));
|
||||
TRY_READ(streamer.drop_octets(current_frame_size));
|
||||
frames.append(TRY_READ(streamer.read_raw_octets(current_frame_size)));
|
||||
}
|
||||
} else if (block->lacing() == Block::Lacing::FixedSize) {
|
||||
} else if (block.lacing() == Block::Lacing::FixedSize) {
|
||||
auto frame_count = TRY_READ(streamer.read_octet()) + 1;
|
||||
auto individual_frame_size = total_frame_content_size / frame_count;
|
||||
for (int i = 0; i < frame_count; i++) {
|
||||
block->add_frame(DECODER_TRY_ALLOC(ByteBuffer::copy(streamer.data(), individual_frame_size)));
|
||||
TRY_READ(streamer.drop_octets(individual_frame_size));
|
||||
}
|
||||
for (int i = 0; i < frame_count; i++)
|
||||
frames.append(TRY_READ(streamer.read_raw_octets(individual_frame_size)));
|
||||
} else {
|
||||
block->add_frame(DECODER_TRY_ALLOC(ByteBuffer::copy(streamer.data(), total_frame_content_size)));
|
||||
TRY_READ(streamer.drop_octets(total_frame_content_size));
|
||||
frames.append(TRY_READ(streamer.read_raw_octets(total_frame_content_size)));
|
||||
}
|
||||
block.set_frames(move(frames));
|
||||
return block;
|
||||
}
|
||||
|
||||
DecoderErrorOr<SampleIterator> Reader::create_sample_iterator(u64 track_number)
|
||||
{
|
||||
auto optional_position = TRY(find_first_top_level_element_with_id("Cluster"sv, CLUSTER_ELEMENT_ID));
|
||||
if (!optional_position.has_value())
|
||||
return DecoderError::corrupted("No clusters are present in the segment"sv);
|
||||
ReadonlyBytes segment_view = m_data.slice(m_segment_contents_position, m_segment_contents_size);
|
||||
|
||||
// We need to have the element ID included so that the iterator knows where it is.
|
||||
auto position = optional_position.value() - get_element_id_size(CLUSTER_ELEMENT_ID) - m_segment_contents_position;
|
||||
|
||||
dbgln_if(MATROSKA_DEBUG, "Creating sample iterator starting at {} relative to segment at {}", position, m_segment_contents_position);
|
||||
return SampleIterator(this->m_mapped_file, segment_view, track_number, position, TRY(segment_information()).timestamp_scale());
|
||||
}
|
||||
|
||||
DecoderErrorOr<void> Reader::seek_to_random_access_point(SampleIterator& iterator, Time timestamp)
|
||||
{
|
||||
(void)iterator;
|
||||
(void)timestamp;
|
||||
return DecoderError::not_implemented();
|
||||
}
|
||||
|
||||
DecoderErrorOr<Block> SampleIterator::next_block()
|
||||
{
|
||||
if (m_position >= m_data.size())
|
||||
return DecoderError::with_description(DecoderErrorCategory::EndOfStream, "Still at end of stream :^)"sv);
|
||||
|
||||
Streamer streamer { m_data };
|
||||
TRY_READ(streamer.seek_to_position(m_position));
|
||||
|
||||
Optional<Block> block;
|
||||
|
||||
while (streamer.has_octet()) {
|
||||
#if MATROSKA_TRACE_DEBUG
|
||||
auto element_position = streamer.position();
|
||||
#endif
|
||||
auto element_id = TRY_READ(streamer.read_variable_size_integer(false));
|
||||
#if MATROSKA_TRACE_DEBUG
|
||||
dbgln("Iterator found element with ID {:#010x} at offset {} within the segment.", element_id, element_position);
|
||||
#endif
|
||||
|
||||
if (element_id == CLUSTER_ELEMENT_ID) {
|
||||
dbgln_if(MATROSKA_DEBUG, " Iterator is parsing new cluster.");
|
||||
m_current_cluster = TRY(parse_cluster(streamer));
|
||||
} else if (element_id == SIMPLE_BLOCK_ID) {
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, " Iterator is parsing new block.");
|
||||
auto candidate_block = TRY(parse_simple_block(streamer));
|
||||
if (candidate_block.track_number() == m_track_id)
|
||||
block = move(candidate_block);
|
||||
} else {
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, " Iterator is skipping unknown element with ID {:#010x}.", element_id);
|
||||
TRY_READ(streamer.read_unknown_element());
|
||||
}
|
||||
|
||||
m_position = streamer.position();
|
||||
if (block.has_value())
|
||||
return block.release_value();
|
||||
}
|
||||
|
||||
m_current_cluster.clear();
|
||||
return DecoderError::with_description(DecoderErrorCategory::EndOfStream, "End of stream"sv);
|
||||
}
|
||||
|
||||
ErrorOr<String> Streamer::read_string()
|
||||
{
|
||||
auto string_length = TRY(read_variable_size_integer());
|
||||
if (remaining() < string_length)
|
||||
return Error::from_string_literal("String length extends past the end of the stream");
|
||||
auto string_value = String(data_as_chars(), string_length);
|
||||
TRY(drop_octets(string_length));
|
||||
TRY(read_raw_octets(string_length));
|
||||
return string_value;
|
||||
}
|
||||
|
||||
|
|
@ -498,13 +729,14 @@ ErrorOr<i64> Streamer::read_variable_size_signed_integer()
|
|||
return result;
|
||||
}
|
||||
|
||||
ErrorOr<void> Streamer::drop_octets(size_t num_octets)
|
||||
ErrorOr<ReadonlyBytes> Streamer::read_raw_octets(size_t num_octets)
|
||||
{
|
||||
if (remaining() < num_octets)
|
||||
return Error::from_string_literal("Tried to drop octets past the end of the stream");
|
||||
ReadonlyBytes result = { data(), num_octets };
|
||||
m_position += num_octets;
|
||||
m_octets_read.last() += num_octets;
|
||||
return {};
|
||||
return result;
|
||||
}
|
||||
|
||||
ErrorOr<u64> Streamer::read_u64()
|
||||
|
|
@ -540,7 +772,17 @@ ErrorOr<double> Streamer::read_float()
|
|||
ErrorOr<void> Streamer::read_unknown_element()
|
||||
{
|
||||
auto element_length = TRY(read_variable_size_integer());
|
||||
return drop_octets(element_length);
|
||||
dbgln_if(MATROSKA_TRACE_DEBUG, "Skipping unknown element of size {}.", element_length);
|
||||
TRY(read_raw_octets(element_length));
|
||||
return {};
|
||||
}
|
||||
|
||||
ErrorOr<void> Streamer::seek_to_position(size_t position)
|
||||
{
|
||||
if (position >= m_data.size())
|
||||
return Error::from_string_literal("Attempted to seek past the end of the stream");
|
||||
m_position = position;
|
||||
return {};
|
||||
}
|
||||
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue