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LibAudio: Add an adjustable buffer size to FlacLoader

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This makes it easier to fine-tune the optimal input buffer size.
This commit is contained in:
kleines Filmröllchen 2021-12-16 23:18:49 +01:00 • committed by Brian Gianforcaro
parent eb1f00a940
commit 9fa3aa84e1
2 changed files with 16 additions and 13 deletions
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14
Userland/Libraries/LibAudio/FlacLoader.cpp
View file

@ -4,12 +4,12 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "AK/StdLibExtras.h"
#include <AK/Debug.h>
#include <AK/FlyString.h>
#include <AK/Format.h>
#include <AK/Math.h>
#include <AK/ScopeGuard.h>
#include <AK/StdLibExtras.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <AK/Try.h>
@ -30,19 +30,15 @@ FlacLoaderPlugin::FlacLoaderPlugin(StringView path)
return;
}
auto maybe_stream = Core::InputFileStream::open_buffered(path);
if (maybe_stream.is_error()) {
m_error = LoaderError { "Can't open file stream" };
return;
}
m_stream = make<FlacInputStream>(maybe_stream.release_value());
auto maybe_stream = Buffered<Core::InputFileStream, FLAC_BUFFER_SIZE> { MUST(Core::File::open(path, Core::OpenMode::ReadOnly)) };
m_stream = make<FlacInputStream<FLAC_BUFFER_SIZE>>(move(maybe_stream));
if (!m_stream)
m_error = LoaderError { "Can't open file stream" };
}
FlacLoaderPlugin::FlacLoaderPlugin(const ByteBuffer& buffer)
{
m_stream = make<FlacInputStream>(InputMemoryStream(buffer));
m_stream = make<FlacInputStream<FLAC_BUFFER_SIZE>>(InputMemoryStream(buffer));
if (!m_stream)
m_error = LoaderError { "Can't open memory stream" };
}
@ -61,7 +57,7 @@ MaybeLoaderError FlacLoaderPlugin::parse_header()
{
InputBitStream bit_input = [&]() -> InputBitStream {
if (m_file) {
return InputBitStream(m_stream->get<Buffered<Core::InputFileStream>>());
return InputBitStream(m_stream->get<Buffered<Core::InputFileStream, FLAC_BUFFER_SIZE>>());
}
return InputBitStream(m_stream->get<InputMemoryStream>());
}();

15
Userland/Libraries/LibAudio/FlacLoader.h
View file

@ -19,15 +19,22 @@
namespace Audio {
class FlacInputStream : public Variant<Buffered<Core::InputFileStream>, InputMemoryStream> {
// Experimentally determined to be a decent buffer size on i686:
// 4K (the default) is slightly worse, and 64K is much worse.
// At sufficiently large buffer sizes, the advantage of infrequent read() calls is outweighed by the memmove() overhead.
// There was no intensive fine-tuning done to determine this value, so improvements may definitely be possible.
constexpr size_t FLAC_BUFFER_SIZE = 8 * KiB;
template<size_t Size = FLAC_BUFFER_SIZE>
class FlacInputStream : public Variant<Buffered<Core::InputFileStream, Size>, InputMemoryStream> {
public:
using Variant<Buffered<Core::InputFileStream>, InputMemoryStream>::Variant;
using Variant<Buffered<Core::InputFileStream, Size>, InputMemoryStream>::Variant;
bool seek(size_t pos)
{
return this->visit(
[&](Buffered<Core::InputFileStream>& buffered) {
[&](Buffered<Core::InputFileStream, Size>& buffered) {
// Discard the buffer, then seek normally.
if (!buffered.discard_or_error(buffered.buffered()))
return false;
@ -142,7 +149,7 @@ private:
// keep track of the start of the data in the FLAC stream to seek back more easily
u64 m_data_start_location { 0 };
OwnPtr<FlacInputStream> m_stream;
OwnPtr<FlacInputStream<FLAC_BUFFER_SIZE>> m_stream;
Optional<FlacFrameHeader> m_current_frame;
Vector<Sample> m_current_frame_data;
u64 m_current_sample_or_frame { 0 };