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Audio: Volume: Fix the ramping and ZC mode align #10704

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Audio: Volume: Fix the ramping and ZC mode align #10704

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263f85e
Audio: Audio Stream: Add function to calculate aligned number of frames
singalsu Apr 15, 2026
f4a3c0c
Audio: Volume: Fix the ramping and ZC mode align
singalsu Apr 15, 2026
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18 changes: 15 additions & 3 deletions src/audio/volume/volume.c
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Original file line number Diff line number Diff line change
Expand Up @@ -556,6 +556,7 @@ static int volume_process(struct processing_module *mod,
struct output_stream_buffer *output_buffers, int num_output_buffers)
{
struct vol_data *cd = module_get_private_data(mod);
struct audio_stream *source = input_buffers[0].data;
uint32_t avail_frames = input_buffers[0].size;
uint32_t frames;
int64_t prev_sum = 0;
Expand All @@ -571,12 +572,23 @@ static int volume_process(struct processing_module *mod,
frames = avail_frames;
} else if (cd->ramp_type == SOF_VOLUME_LINEAR_ZC) {
/* with ZC ramping look for next ZC offset */
frames = cd->zc_get(input_buffers[0].data, cd->vol_ramp_frames, &prev_sum);
frames = cd->zc_get(source, cd->vol_ramp_frames, &prev_sum);
/* Align frames count to audio stream constraints */
frames = audio_stream_align_frames_round_up(source, frames);
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@lyakh lyakh Apr 16, 2026

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is rounding up correct? Wouldn't that grab incomplete frames? Same below. And if you round down then you presumably wouldn't need to add lines 589-590

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@singalsu singalsu Apr 16, 2026

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A round to nearest (up or down) would be best for ZC but need to check if zero frames need more handling.

} else {
/* without ZC process max ramp chunk */
frames = cd->vol_ramp_frames;
/* During volume ramp align the number of frames used in this
* gain step. Align up since with low rates this would typically
* become zero.
*/
frames = audio_stream_align_frames_round_up(source, cd->vol_ramp_frames);
}

/* Cancel the gain step for ZC or smaller ramp step if it exceeds
* the available frames.
*/
if (frames > avail_frames)
frames = avail_frames;

if (!cd->ramp_finished) {
volume_ramp(mod);
cd->vol_ramp_elapsed_frames += frames;
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32 changes: 32 additions & 0 deletions src/include/sof/audio/audio_stream.h
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Expand Up @@ -612,6 +612,38 @@ audio_stream_avail_frames_aligned(const struct audio_stream *source,
return MIN(src_frames, sink_frames);
}

/**
* Rounds down a frame count to meet the alignment constraint of the stream.
* @param stream Audio stream with alignment requirements set.
* @param frames Frame count to round down.
* @return Largest aligned frame count less than or equal to frames.
*/
static inline uint32_t audio_stream_align_frames_round_down(const struct audio_stream *stream,
uint32_t frames)
{
uint16_t align = stream->runtime_stream_params.align_frame_cnt;

return (frames / align) * align;
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@lyakh lyakh Apr 16, 2026

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can alignment be not a power of 2? We have multiple locations in SOF where we enforce that assumption and then use bit-wise operations apply such power-of-2 alignment. Either way you can use ROUND_DOWN() for the generic case or ALIGN_DOWN() for the power-of-2 case

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@singalsu singalsu Apr 16, 2026

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The align can be any positive integer number. ROUND_DOWN is some operation with modulo and ALIGN_DOWN is for power of 2. I prefer this simple equation.

}

/**
* Rounds up a frame count to meet the alignment constraint of the stream.
* @param stream Audio stream with alignment requirements set.
* @param frames Frame count to round up.
* @return Smallest aligned frame count greater than or equal to frames.
*/
static inline uint32_t audio_stream_align_frames_round_up(const struct audio_stream *stream,
uint32_t frames)
{
uint16_t align = stream->runtime_stream_params.align_frame_cnt;
uint32_t aligned_frames = (frames / align) * align;

if (aligned_frames < frames)
aligned_frames += align;
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@lyakh lyakh Apr 16, 2026

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ROUND_UP() or ALIGN_UP()

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@singalsu singalsu Apr 16, 2026

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I prefer this simple equation to know exactly what it does.

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@singalsu singalsu Apr 16, 2026

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So, I reject your reject.


return aligned_frames;
}

/**
* Updates the buffer state after writing to the buffer.
* @param buffer Buffer to update.
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