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LibAudio: Use specified bit depth directly

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We report a rounded up PCM sample format to the outside, but use the
exact bit depth as specified in header and frames.

This makes the three FLAC spec tests with a a bit depth of 20 pass.
This commit is contained in:
kleines Filmröllchen 2023-03-14 19:24:18 +01:00 • committed by Linus Groh
parent a2d13c47bd
commit b2a018ee59
Notes: sideshowbarker 2024-07-17 07:31:31 +09:00
3 changed files with 36 additions and 29 deletions
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53
Userland/Libraries/LibAudio/FlacLoader.cpp
View file

@ -65,11 +65,11 @@ MaybeLoaderError FlacLoaderPlugin::parse_header()
BigEndianInputBitStream bit_input { MaybeOwned<Stream>(*m_stream) };
// A mixture of VERIFY and the non-crashing TRY().
#define FLAC_VERIFY(check, category, msg) \
do { \
if (!(check)) { \
return LoaderError { category, static_cast<size_t>(m_data_start_location), DeprecatedString::formatted("FLAC header: {}", msg) }; \
} \
#define FLAC_VERIFY(check, category, msg) \
do { \
if (!(check)) { \
return LoaderError { category, LOADER_TRY(m_stream->tell()), DeprecatedString::formatted("FLAC header: {}", msg) }; \
} \
} while (0)
// Magic number
@ -94,18 +94,18 @@ MaybeLoaderError FlacLoaderPlugin::parse_header()
FLAC_VERIFY(m_sample_rate <= 655350, LoaderError::Category::Format, "Sample rate");
m_num_channels = LOADER_TRY(streaminfo_data.read_bits<u8>(3)) + 1; // 0 = one channel
u8 bits_per_sample = LOADER_TRY(streaminfo_data.read_bits<u8>(5)) + 1;
if (bits_per_sample == 8) {
m_bits_per_sample = LOADER_TRY(streaminfo_data.read_bits<u8>(5)) + 1;
if (m_bits_per_sample <= 8) {
// FIXME: Signed/Unsigned issues?
m_sample_format = PcmSampleFormat::Uint8;
} else if (bits_per_sample == 16) {
} else if (m_bits_per_sample <= 16) {
m_sample_format = PcmSampleFormat::Int16;
} else if (bits_per_sample == 24) {
} else if (m_bits_per_sample <= 24) {
m_sample_format = PcmSampleFormat::Int24;
} else if (bits_per_sample == 32) {
} else if (m_bits_per_sample <= 32) {
m_sample_format = PcmSampleFormat::Int32;
} else {
FLAC_VERIFY(false, LoaderError::Category::Format, "Sample bit depth invalid");
FLAC_VERIFY(false, LoaderError::Category::Format, "Sample bit depth too large");
}
m_total_samples = LOADER_TRY(streaminfo_data.read_bits<u64>(36));
@ -387,7 +387,7 @@ LoaderSamples FlacLoaderPlugin::next_frame()
FLAC_VERIFY(channel_type_num < 0b1011, LoaderError::Category::Format, "Channel assignment");
FlacFrameChannelType channel_type = (FlacFrameChannelType)channel_type_num;
PcmSampleFormat bit_depth = TRY(convert_bit_depth_code(LOADER_TRY(bit_stream.read_bits<u8>(3))));
u8 bit_depth = TRY(convert_bit_depth_code(LOADER_TRY(bit_stream.read_bits<u8>(3))));
reserved_bit = LOADER_TRY(bit_stream.read_bit());
FLAC_VERIFY(reserved_bit == 0, LoaderError::Category::Format, "Reserved frame header end bit");
@ -417,7 +417,7 @@ LoaderSamples FlacLoaderPlugin::next_frame()
// TODO: check header checksum, see above
[[maybe_unused]] u8 checksum = LOADER_TRY(bit_stream.read_bits<u8>(8));
dbgln_if(AFLACLOADER_DEBUG, "Frame: {} samples, {}bit {}Hz, channeltype {:x}, {} number {}, header checksum {}", sample_count, pcm_bits_per_sample(bit_depth), frame_sample_rate, channel_type_num, blocking_strategy ? "sample" : "frame", m_current_sample_or_frame, checksum);
dbgln_if(AFLACLOADER_DEBUG, "Frame: {} samples, {}bit {}Hz, channeltype {:x}, {} number {}, header checksum {}", sample_count, bit_depth, frame_sample_rate, channel_type_num, blocking_strategy ? "sample" : "frame", m_current_sample_or_frame, checksum);
m_current_frame = FlacFrameHeader {
sample_count,
@ -445,8 +445,8 @@ LoaderSamples FlacLoaderPlugin::next_frame()
[[maybe_unused]] u16 footer_checksum = LOADER_TRY(bit_stream.read_bits<u16>(16));
dbgln_if(AFLACLOADER_DEBUG, "Subframe footer checksum: {}", footer_checksum);
float sample_rescale = 1 / static_cast<float>(1 << (pcm_bits_per_sample(m_current_frame->bit_depth) - 1));
dbgln_if(AFLACLOADER_DEBUG, "Sample rescaled from {} bits: factor {:.1f}", pcm_bits_per_sample(m_current_frame->bit_depth), sample_rescale);
float sample_rescale = 1 / static_cast<float>(1 << (m_current_frame->bit_depth - 1));
dbgln_if(AFLACLOADER_DEBUG, "Sample rescaled from {} bits: factor {:.8f}", m_current_frame->bit_depth, sample_rescale);
FixedArray<Sample> samples = TRY(FixedArray<Sample>::create(m_current_frame->sample_count));
@ -559,20 +559,25 @@ ErrorOr<u32, LoaderError> FlacLoaderPlugin::convert_sample_rate_code(u8 sample_r
}
// 11.22.6. SAMPLE SIZE
ErrorOr<PcmSampleFormat, LoaderError> FlacLoaderPlugin::convert_bit_depth_code(u8 bit_depth_code)
ErrorOr<u8, LoaderError> FlacLoaderPlugin::convert_bit_depth_code(u8 bit_depth_code)
{
switch (bit_depth_code) {
case 0:
return m_sample_format;
return m_bits_per_sample;
case 1:
return PcmSampleFormat::Uint8;
case 4:
return PcmSampleFormat::Int16;
case 6:
return PcmSampleFormat::Int24;
return 8;
case 2:
return 12;
case 3:
case 7:
return LoaderError { LoaderError::Category::Format, static_cast<size_t>(m_current_sample_or_frame), "Reserved sample size" };
case 4:
return 16;
case 5:
return 20;
case 6:
return 24;
case 7:
return 32;
default:
return LoaderError { LoaderError::Category::Format, static_cast<size_t>(m_current_sample_or_frame), DeprecatedString::formatted("Unsupported sample size {}", bit_depth_code) };
}
@ -589,7 +594,7 @@ u8 frame_channel_type_to_channel_count(FlacFrameChannelType channel_type)
// 11.25. SUBFRAME_HEADER
ErrorOr<FlacSubframeHeader, LoaderError> FlacLoaderPlugin::next_subframe_header(BigEndianInputBitStream& bit_stream, u8 channel_index)
{
u8 bits_per_sample = static_cast<u16>(pcm_bits_per_sample(m_current_frame->bit_depth));
u8 bits_per_sample = m_current_frame->bit_depth;
// For inter-channel correlation, the side channel needs an extra bit for its samples
switch (m_current_frame->channels) {

10
Userland/Libraries/LibAudio/FlacLoader.h
View file

@ -85,14 +85,16 @@ private:
// Converters for special coding used in frame headers
ALWAYS_INLINE ErrorOr<u32, LoaderError> convert_sample_count_code(u8 sample_count_code);
ALWAYS_INLINE ErrorOr<u32, LoaderError> convert_sample_rate_code(u8 sample_rate_code);
ALWAYS_INLINE ErrorOr<PcmSampleFormat, LoaderError> convert_bit_depth_code(u8 bit_depth_code);
ALWAYS_INLINE ErrorOr<u8, LoaderError> convert_bit_depth_code(u8 bit_depth_code);
bool should_insert_seekpoint_at(u64 sample_index) const;
// Data obtained directly from the FLAC metadata: many values have specific bit counts
u32 m_sample_rate { 0 }; // 20 bit
u8 m_num_channels { 0 }; // 3 bit
PcmSampleFormat m_sample_format; // 5 bits for the integer bit depth
u32 m_sample_rate { 0 }; // 20 bit
u8 m_num_channels { 0 }; // 3 bit
u8 m_bits_per_sample { 0 }; // 5 bits for the integer bit depth
// Externally visible format; the smallest integer format that's larger than the precise bit depth.
PcmSampleFormat m_sample_format;
// Blocks are units of decoded audio data
u16 m_min_block_size { 0 };
u16 m_max_block_size { 0 };

2
Userland/Libraries/LibAudio/FlacTypes.h
View file

@ -79,7 +79,7 @@ struct FlacFrameHeader {
u32 sample_count;
u32 sample_rate;
FlacFrameChannelType channels;
PcmSampleFormat bit_depth;
u8 bit_depth;
};
// 11.25. SUBFRAME_HEADER