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LibVideo/VP9: Choose whether/how to show new frames using an enum

There are three mutually exclusive frame-showing states:
- Show no new frame, only store the frame as a reference.
- Show a newly decoded frame.
- Show frame from the reference frame store.
Since they are mutually exclusive, using an enum rather than two bools
makes more sense.
This commit is contained in:
Zaggy1024 2022-11-22 21:36:36 -06:00 committed by Andreas Kling
parent befcd479ae
commit 3259c99cab
4 changed files with 24 additions and 9 deletions

View file

@ -237,17 +237,26 @@ struct PersistentBlockContext {
u8 segment_id { 0 };
};
enum class FrameShowMode {
CreateAndShowNewFrame,
ShowExistingFrame,
DoNotShowFrame,
};
struct FrameContext {
public:
u8 profile { 0 };
bool shows_existing_frame() const { return m_show_existing_frame; }
u8 existing_frame_index() const { return m_existing_frame_index; }
bool shows_a_frame() const { return m_frame_show_mode != FrameShowMode::DoNotShowFrame; }
bool shows_a_new_frame() const { return m_frame_show_mode == FrameShowMode::CreateAndShowNewFrame; }
bool shows_existing_frame() const { return m_frame_show_mode == FrameShowMode::ShowExistingFrame; }
void set_frame_hidden() { m_frame_show_mode = FrameShowMode::DoNotShowFrame; }
void set_existing_frame_to_show(u8 index)
{
m_show_existing_frame = true;
m_frame_show_mode = FrameShowMode::ShowExistingFrame;
m_existing_frame_index = index;
}
u8 existing_frame_index() const { return m_existing_frame_index; }
Gfx::Size<u32> size() const { return m_size; }
ErrorOr<void> set_size(Gfx::Size<u32> size)
@ -273,7 +282,7 @@ public:
private:
friend struct TileContext;
bool m_show_existing_frame { false };
FrameShowMode m_frame_show_mode { FrameShowMode::CreateAndShowNewFrame };
u8 m_existing_frame_index { 0 };
Gfx::Size<u32> m_size { 0, 0 };

View file

@ -69,7 +69,7 @@ DecoderErrorOr<void> Decoder::decode_frame(ReadonlyBytes frame_data)
// This is handled by update_reference_frames.
// 4. The output process as specified in section 8.9 is invoked.
if (m_parser->m_show_frame)
if (frame_context.shows_a_frame())
TRY(create_video_frame(frame_context));
// 5. The reference frame update process as specified in section 8.10 is invoked.
@ -79,6 +79,12 @@ DecoderErrorOr<void> Decoder::decode_frame(ReadonlyBytes frame_data)
DecoderErrorOr<void> Decoder::create_video_frame(FrameContext const& frame_context)
{
// (8.9) Output process
// FIXME: If show_existing_frame is set, output from FrameStore[frame_to_show_map_index] here instead.
// FIXME: The math isn't entirely accurate to spec. output_uv_size is probably incorrect for certain
// sizes, as the spec seems to prefer that the halved sizes be ceiled.
u32 decoded_y_width = frame_context.columns() * 8;
Gfx::Size<u32> output_y_size = frame_context.size();
auto decoded_uv_width = decoded_y_width >> m_parser->m_subsampling_x;

View file

@ -104,7 +104,7 @@ DecoderErrorOr<FrameContext> Parser::parse_frame(ReadonlyBytes frame_data)
TRY(refresh_probs());
m_previous_frame_size = frame_context.size();
m_previous_show_frame = m_show_frame;
m_previous_show_frame = frame_context.shows_a_frame();
return frame_context;
}
@ -171,7 +171,8 @@ DecoderErrorOr<FrameContext> Parser::uncompressed_header()
m_last_frame_type = m_frame_type;
m_frame_type = TRY(read_frame_type());
m_show_frame = TRY_READ(m_bit_stream->read_bit());
if (!TRY_READ(m_bit_stream->read_bit()))
frame_context.set_frame_hidden();
m_error_resilient_mode = TRY_READ(m_bit_stream->read_bit());
Gfx::Size<u32> frame_size;
@ -185,7 +186,7 @@ DecoderErrorOr<FrameContext> Parser::uncompressed_header()
m_refresh_frame_flags = 0xFF;
m_frame_is_intra = true;
} else {
m_frame_is_intra = !m_show_frame && TRY_READ(m_bit_stream->read_bit());
m_frame_is_intra = !frame_context.shows_a_frame() && TRY_READ(m_bit_stream->read_bit());
if (!m_error_resilient_mode) {
m_reset_frame_context = TRY_READ(m_bit_stream->read_bits(2));

View file

@ -149,7 +149,6 @@ private:
bool m_loop_filter_delta_enabled { false };
FrameType m_frame_type { FrameType::KeyFrame };
FrameType m_last_frame_type { FrameType::KeyFrame };
bool m_show_frame { false };
bool m_error_resilient_mode { false };
bool m_frame_is_intra { false };
u8 m_reset_frame_context { 0 };