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[PATCH v2 11/17] audio: replace the resampling loop in audio_pcm_sw_read
From: |
Volker Rümelin |
Subject: |
[PATCH v2 11/17] audio: replace the resampling loop in audio_pcm_sw_read() |
Date: |
Mon, 6 Feb 2023 19:52:31 +0100 |
Replace the resampling loop in audio_pcm_sw_read() with the new
function audio_pcm_sw_resample_in(). Unlike the old resample
loop the new function will try to consume input frames even if
the output buffer is full. This is necessary when downsampling
to avoid reading less audio frames than calculated in advance.
The loop was unrolled to avoid complicated loop control conditions
in this case.
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
---
audio/audio.c | 59 ++++++++++++++++++++++++++++++---------------------
1 file changed, 35 insertions(+), 24 deletions(-)
diff --git a/audio/audio.c b/audio/audio.c
index e18b5e98c5..9e9c03a42e 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -543,11 +543,43 @@ static size_t audio_pcm_hw_conv_in(HWVoiceIn *hw, void
*pcm_buf, size_t samples)
/*
* Soft voice (capture)
*/
+static void audio_pcm_sw_resample_in(SWVoiceIn *sw,
+ size_t frames_in_max, size_t frames_out_max,
+ size_t *total_in, size_t *total_out)
+{
+ HWVoiceIn *hw = sw->hw;
+ struct st_sample *src, *dst;
+ size_t live, rpos, frames_in, frames_out;
+
+ live = hw->total_samples_captured - sw->total_hw_samples_acquired;
+ rpos = audio_ring_posb(hw->conv_buf.pos, live, hw->conv_buf.size);
+
+ /* resample conv_buf from rpos to end of buffer */
+ src = hw->conv_buf.buffer + rpos;
+ frames_in = MIN(frames_in_max, hw->conv_buf.size - rpos);
+ dst = sw->resample_buf.buffer;
+ frames_out = frames_out_max;
+ st_rate_flow(sw->rate, src, dst, &frames_in, &frames_out);
+ rpos += frames_in;
+ *total_in = frames_in;
+ *total_out = frames_out;
+
+ /* resample conv_buf from start of buffer if there are input frames left */
+ if (frames_in_max - frames_in && rpos == hw->conv_buf.size) {
+ src = hw->conv_buf.buffer;
+ frames_in = frames_in_max - frames_in;
+ dst += frames_out;
+ frames_out = frames_out_max - frames_out;
+ st_rate_flow(sw->rate, src, dst, &frames_in, &frames_out);
+ *total_in += frames_in;
+ *total_out += frames_out;
+ }
+}
+
static size_t audio_pcm_sw_read(SWVoiceIn *sw, void *buf, size_t size)
{
HWVoiceIn *hw = sw->hw;
- size_t samples, live, ret = 0, swlim, isamp, osamp, rpos, total = 0;
- struct st_sample *src, *dst = sw->resample_buf.buffer;
+ size_t samples, live, ret, swlim, total;
live = hw->total_samples_captured - sw->total_hw_samples_acquired;
if (!live) {
@@ -558,33 +590,12 @@ static size_t audio_pcm_sw_read(SWVoiceIn *sw, void *buf,
size_t size)
return 0;
}
- rpos = audio_ring_posb(hw->conv_buf.pos, live, hw->conv_buf.size);
-
samples = size / sw->info.bytes_per_frame;
swlim = (live * sw->ratio) >> 32;
swlim = MIN (swlim, samples);
- while (swlim) {
- src = hw->conv_buf.buffer + rpos;
- if (hw->conv_buf.pos > rpos) {
- isamp = hw->conv_buf.pos - rpos;
- } else {
- isamp = hw->conv_buf.size - rpos;
- }
-
- if (!isamp) {
- break;
- }
- osamp = swlim;
-
- st_rate_flow (sw->rate, src, dst, &isamp, &osamp);
- swlim -= osamp;
- rpos = (rpos + isamp) % hw->conv_buf.size;
- dst += osamp;
- ret += osamp;
- total += isamp;
- }
+ audio_pcm_sw_resample_in(sw, live, swlim, &total, &ret);
if (!hw->pcm_ops->volume_in) {
mixeng_volume(sw->resample_buf.buffer, ret, &sw->vol);
--
2.35.3
- [PATCH v2 05/17] audio: remove sw == NULL check, (continued)
- [PATCH v2 05/17] audio: remove sw == NULL check, Volker Rümelin, 2023/02/06
- [PATCH v2 07/17] audio: don't misuse audio_pcm_sw_write(), Volker Rümelin, 2023/02/06
- [PATCH v2 08/17] audio: remove unused noop_conv() function, Volker Rümelin, 2023/02/06
- [PATCH v2 09/17] audio/mixeng: calculate number of input frames, Volker Rümelin, 2023/02/06
- [PATCH v2 10/17] audio: wire up st_rate_frames_in(), Volker Rümelin, 2023/02/06
- [PATCH v2 11/17] audio: replace the resampling loop in audio_pcm_sw_read(),
Volker Rümelin <=
- [PATCH v2 04/17] audio: replace the resampling loop in audio_pcm_sw_write(), Volker Rümelin, 2023/02/06
- [PATCH v2 12/17] audio: rename variables in audio_pcm_sw_read(), Volker Rümelin, 2023/02/06
- [PATCH v2 13/17] audio/mixeng: calculate number of output frames, Volker Rümelin, 2023/02/06
- [PATCH v2 15/17] audio: handle leftover audio frame from upsampling, Volker Rümelin, 2023/02/06
- [PATCH v2 14/17] audio: wire up st_rate_frames_out(), Volker Rümelin, 2023/02/06