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Avoid deinterleaving when possible #913

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Merged
sbooth merged 2 commits into from
May 24, 2026
Merged

Avoid deinterleaving when possible #913

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54b47a4
Avoid deinterleaving when possible
sbooth May 23, 2026
7d4b331
Correct frame count
sbooth May 24, 2026
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20 changes: 3 additions & 17 deletions Sources/CSFBAudioEngine/Decoders/SFBMPEGDecoder.m
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Original file line number Diff line number Diff line change
Expand Up @@ -312,7 +312,7 @@ - (BOOL)openReturningError:(NSError **)error {

_processingFormat = [[AVAudioFormat alloc] initWithCommonFormat:AVAudioPCMFormatFloat32
sampleRate:rate
interleaved:NO
interleaved:YES
channelLayout:channelLayout];

size_t bufferSizeBytes = mpg123_outblock(_mpg123);
Expand Down Expand Up @@ -435,22 +435,8 @@ - (BOOL)decodeIntoBuffer:(AVAudioPCMBuffer *)buffer frameLength:(AVAudioFrameCou
return NO;
}

// Deinterleave the samples
AVAudioFrameCount framesDecoded =
(AVAudioFrameCount)(bytesDecoded / (sizeof(float) * _buffer.format.channelCount));

float *const *floatChannelData = _buffer.floatChannelData;
AVAudioChannelCount channelCount = _buffer.format.channelCount;
for (AVAudioChannelCount channel = 0; channel < channelCount; ++channel) {
const float *input = (float *)audioData + channel;
float *output = floatChannelData[channel];
for (AVAudioFrameCount frame = 0; frame < framesDecoded; ++frame) {
*output++ = *input;
input += channelCount;
}
}

_buffer.frameLength = framesDecoded;
memcpy(_buffer.audioBufferList->mBuffers[0].mData, audioData, bytesDecoded);
_buffer.frameLength = (AVAudioFrameCount)(bytesDecoded / (_buffer.stride * sizeof(float)));
}

_framePosition += framesProcessed;
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15 changes: 2 additions & 13 deletions Sources/CSFBAudioEngine/Decoders/SFBMusepackDecoder.m
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Original file line number Diff line number Diff line change
Expand Up @@ -192,7 +192,7 @@ - (BOOL)openReturningError:(NSError **)error {

_processingFormat = [[AVAudioFormat alloc] initWithCommonFormat:AVAudioPCMFormatFloat32
sampleRate:streaminfo.sample_freq
interleaved:NO
interleaved:YES
channelLayout:channelLayout];

// Set up the source format
Expand Down Expand Up @@ -324,18 +324,7 @@ - (BOOL)decodeIntoBuffer:(AVAudioPCMBuffer *)buffer frameLength:(AVAudioFrameCou
AVAudioChannelCount channelCount = _buffer.format.channelCount;
vDSP_vclip((float *)frame.buffer, 1, &minValue, &maxValue, (float *)frame.buffer, 1,
frame.samples * channelCount);

// Deinterleave the normalized samples
float *const *floatChannelData = _buffer.floatChannelData;
for (AVAudioChannelCount channel = 0; channel < channelCount; ++channel) {
const float *input = (float *)frame.buffer + channel;
float *output = floatChannelData[channel] + _buffer.frameLength;
for (uint32_t sample = 0; sample < frame.samples; ++sample) {
*output++ = *input;
input += channelCount;
}
}

memcpy(_buffer.audioBufferList->mBuffers[0].mData, frame.buffer, frame.samples * channelCount * sizeof(float));
_buffer.frameLength = frame.samples;
#endif /* MPC_FIXED_POINT */
}
Expand Down