From 8a81abeeb2e17630c366fccbd99ce20eac328819 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Volker=20R=C3=BCmelin?= Date: Fri, 24 Feb 2023 20:05:44 +0100 Subject: audio: replace the resampling loop in audio_pcm_sw_write() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Replace the resampling loop in audio_pcm_sw_write() with the new function audio_pcm_sw_resample_out(). 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 Acked-by: Marc-André Lureau Signed-off-by: Volker Rümelin Message-Id: <20230224190555.7409-4-vr_qemu@t-online.de> --- audio/audio.c | 63 ++++++++++++++++++++++++++++++++++------------------------- 1 file changed, 36 insertions(+), 27 deletions(-) (limited to 'audio') diff --git a/audio/audio.c b/audio/audio.c index a399147..4412b5f 100644 --- a/audio/audio.c +++ b/audio/audio.c @@ -673,11 +673,44 @@ static void audio_pcm_hw_clip_out(HWVoiceOut *hw, void *pcm_buf, size_t len) /* * Soft voice (playback) */ +static void audio_pcm_sw_resample_out(SWVoiceOut *sw, + size_t frames_in_max, size_t frames_out_max, + size_t *total_in, size_t *total_out) +{ + HWVoiceOut *hw = sw->hw; + struct st_sample *src, *dst; + size_t live, wpos, frames_in, frames_out; + + live = sw->total_hw_samples_mixed; + wpos = (hw->mix_buf.pos + live) % hw->mix_buf.size; + + /* write to mix_buf from wpos to end of buffer */ + src = sw->resample_buf.buffer; + frames_in = frames_in_max; + dst = hw->mix_buf.buffer + wpos; + frames_out = MIN(frames_out_max, hw->mix_buf.size - wpos); + st_rate_flow_mix(sw->rate, src, dst, &frames_in, &frames_out); + wpos += frames_out; + *total_in = frames_in; + *total_out = frames_out; + + /* write to mix_buf from start of buffer if there are input frames left */ + if (frames_in_max - frames_in > 0 && wpos == hw->mix_buf.size) { + src += frames_in; + frames_in = frames_in_max - frames_in; + dst = hw->mix_buf.buffer; + frames_out = frames_out_max - frames_out; + st_rate_flow_mix(sw->rate, src, dst, &frames_in, &frames_out); + *total_in += frames_in; + *total_out += frames_out; + } +} + static size_t audio_pcm_sw_write(SWVoiceOut *sw, void *buf, size_t size) { - size_t hwsamples, samples, isamp, osamp, wpos, live, dead, left, blck; + size_t hwsamples, samples, live, dead; size_t hw_free; - size_t ret = 0, pos = 0, total = 0; + size_t ret, total; if (!sw) { return size; @@ -698,8 +731,6 @@ static size_t audio_pcm_sw_write(SWVoiceOut *sw, void *buf, size_t size) return 0; } - wpos = (sw->hw->mix_buf.pos + live) % hwsamples; - dead = hwsamples - live; hw_free = audio_pcm_hw_get_free(sw->hw); hw_free = hw_free > live ? hw_free - live : 0; @@ -713,29 +744,7 @@ static size_t audio_pcm_sw_write(SWVoiceOut *sw, void *buf, size_t size) } } - while (samples) { - dead = hwsamples - live; - left = hwsamples - wpos; - blck = MIN (dead, left); - if (!blck) { - break; - } - isamp = samples; - osamp = blck; - st_rate_flow_mix ( - sw->rate, - sw->resample_buf.buffer + pos, - sw->hw->mix_buf.buffer + wpos, - &isamp, - &osamp - ); - ret += isamp; - samples -= isamp; - pos += isamp; - live += osamp; - wpos = (wpos + osamp) % hwsamples; - total += osamp; - } + audio_pcm_sw_resample_out(sw, samples, MIN(dead, hw_free), &ret, &total); sw->total_hw_samples_mixed += total; sw->empty = sw->total_hw_samples_mixed == 0; -- cgit v1.1