[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PULL 25/27] audio: handle leftover audio frame from upsampling
From: |
marcandre . lureau |
Subject: |
[PULL 25/27] audio: handle leftover audio frame from upsampling |
Date: |
Mon, 6 Mar 2023 10:52:00 +0400 |
From: Volker Rümelin <vr_qemu@t-online.de>
Upsampling may leave one remaining audio frame in the input
buffer. The emulated audio playback devices are currently
resposible to write this audio frame again in the next write
cycle. Push that task down to audio_pcm_sw_write.
This is another step towards an audio callback interface that
guarantees that when audio frontends are told they can write
n audio frames, they can actually do so.
Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Message-Id: <20230224190555.7409-13-vr_qemu@t-online.de>
---
audio/audio_template.h | 6 ++++++
audio/audio.c | 34 ++++++++++++++++++++++++++++------
2 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/audio/audio_template.h b/audio/audio_template.h
index a0b653f52c..0d8aab6fad 100644
--- a/audio/audio_template.h
+++ b/audio/audio_template.h
@@ -138,6 +138,12 @@ static int glue (audio_pcm_sw_alloc_resources_, TYPE) (SW
*sw)
return -1;
}
+ /*
+ * Allocate one additional audio frame that is needed for upsampling
+ * if the resample buffer size is small. For large buffer sizes take
+ * care of overflows.
+ */
+ samples = samples < INT_MAX ? samples + 1 : INT_MAX;
sw->resample_buf.buffer = g_new0(st_sample, samples);
sw->resample_buf.size = samples;
sw->resample_buf.pos = 0;
diff --git a/audio/audio.c b/audio/audio.c
index dad17e59b8..4836ab8ca8 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -731,16 +731,21 @@ static size_t audio_pcm_sw_write(SWVoiceOut *sw, void
*buf, size_t buf_len)
hw_free = hw_free > live ? hw_free - live : 0;
frames_out_max = MIN(dead, hw_free);
sw_max = st_rate_frames_in(sw->rate, frames_out_max);
- fe_max = MIN(buf_len / sw->info.bytes_per_frame, sw->resample_buf.size);
+ fe_max = MIN(buf_len / sw->info.bytes_per_frame + sw->resample_buf.pos,
+ sw->resample_buf.size);
frames_in_max = MIN(sw_max, fe_max);
if (!frames_in_max) {
return 0;
}
- sw->conv(sw->resample_buf.buffer, buf, frames_in_max);
- if (!sw->hw->pcm_ops->volume_out) {
- mixeng_volume(sw->resample_buf.buffer, frames_in_max, &sw->vol);
+ if (frames_in_max > sw->resample_buf.pos) {
+ sw->conv(sw->resample_buf.buffer + sw->resample_buf.pos,
+ buf, frames_in_max - sw->resample_buf.pos);
+ if (!sw->hw->pcm_ops->volume_out) {
+ mixeng_volume(sw->resample_buf.buffer + sw->resample_buf.pos,
+ frames_in_max - sw->resample_buf.pos, &sw->vol);
+ }
}
audio_pcm_sw_resample_out(sw, frames_in_max, frames_out_max,
@@ -749,6 +754,22 @@ static size_t audio_pcm_sw_write(SWVoiceOut *sw, void
*buf, size_t buf_len)
sw->total_hw_samples_mixed += total_out;
sw->empty = sw->total_hw_samples_mixed == 0;
+ /*
+ * Upsampling may leave one audio frame in the resample buffer. Decrement
+ * total_in by one if there was a leftover frame from the previous resample
+ * pass in the resample buffer. Increment total_in by one if the current
+ * resample pass left one frame in the resample buffer.
+ */
+ if (frames_in_max - total_in == 1) {
+ /* copy one leftover audio frame to the beginning of the buffer */
+ *sw->resample_buf.buffer = *(sw->resample_buf.buffer + total_in);
+ total_in += 1 - sw->resample_buf.pos;
+ sw->resample_buf.pos = 1;
+ } else if (total_in >= sw->resample_buf.pos) {
+ total_in -= sw->resample_buf.pos;
+ sw->resample_buf.pos = 0;
+ }
+
#ifdef DEBUG_OUT
dolog (
"%s: write size %zu written %zu total mixed %zu\n",
@@ -1155,8 +1176,9 @@ static void audio_run_out (AudioState *s)
} else {
free = 0;
}
- if (free > 0) {
- free = MIN(free, sw->resample_buf.size);
+ if (free > sw->resample_buf.pos) {
+ free = MIN(free, sw->resample_buf.size)
+ - sw->resample_buf.pos;
sw->callback.fn(sw->callback.opaque,
free * sw->info.bytes_per_frame);
}
--
2.39.2
- [PULL 15/27] audio: make the resampling code greedy, (continued)
- [PULL 15/27] audio: make the resampling code greedy, marcandre . lureau, 2023/03/06
- [PULL 16/27] audio: replace the resampling loop in audio_pcm_sw_write(), marcandre . lureau, 2023/03/06
- [PULL 17/27] audio: remove sw == NULL check, marcandre . lureau, 2023/03/06
- [PULL 18/27] audio: rename variables in audio_pcm_sw_write(), marcandre . lureau, 2023/03/06
- [PULL 19/27] audio: don't misuse audio_pcm_sw_write(), marcandre . lureau, 2023/03/06
- [PULL 20/27] audio: remove unused noop_conv() function, marcandre . lureau, 2023/03/06
- [PULL 22/27] audio: replace the resampling loop in audio_pcm_sw_read(), marcandre . lureau, 2023/03/06
- [PULL 21/27] audio: make playback packet length calculation exact, marcandre . lureau, 2023/03/06
- [PULL 23/27] audio: rename variables in audio_pcm_sw_read(), marcandre . lureau, 2023/03/06
- [PULL 24/27] audio: make recording packet length calculation exact, marcandre . lureau, 2023/03/06
- [PULL 25/27] audio: handle leftover audio frame from upsampling,
marcandre . lureau <=
- [PULL 26/27] audio/audio_template: substitute sw->hw with hw, marcandre . lureau, 2023/03/06
- [PULL 27/27] audio: remove sw->ratio, marcandre . lureau, 2023/03/06
- Re: [PULL 00/27] Audio patches, Peter Maydell, 2023/03/06