The current value, 8, is too low to be really useful.
The heuristic tries to allocate enough room for 10 seconds.
Signed-off-by: Nicolas George <geo...@nsup.org>
---
ffmpeg.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
On my hardware, recording from v4l2 and ALSA produces ALSA underruns if the
message queue is below ~256-512.
diff --git a/ffmpeg.c b/ffmpeg.c
index a52de20..990ce9e 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -3412,9 +3412,29 @@ static void free_input_threads(void)
}
}
+static int eval_thread_queue_size(InputFile *f)
+{
+ int i, s;
+ int64_t sec = 10, fps = 0;
+
+ for (i = 0; i < f->ctx->nb_streams; i++) {
+ AVStream *st = f->ctx->streams[i];
+ AVCodecContext *c = st->codec;
+ if (c->sample_rate && c->frame_size) {
+ fps += sec * (c->sample_rate / c->frame_size + 1);
+ } else if (st->avg_frame_rate.num && st->avg_frame_rate.den) {
+ fps += 1 + av_rescale(sec, st->avg_frame_rate.num,
st->avg_frame_rate.den);
+ } else {
+ fps += 25 * sec;
+ }
+ }
+ s = FFMAX(3, FFMIN(20, av_log2(fps) + 1));
+ return 1 << s;
+}
+
static int init_input_threads(void)
{
- int i, ret;
+ int i, ret, qs;
if (nb_input_files == 1)
return 0;
@@ -3425,8 +3445,10 @@ static int init_input_threads(void)
if (f->ctx->pb ? !f->ctx->pb->seekable :
strcmp(f->ctx->iformat->name, "lavfi"))
f->non_blocking = 1;
+ qs = eval_thread_queue_size(f);
+ av_log(f->ctx, AV_LOG_VERBOSE, "Using input thread with queue size
%d\n", qs);
ret = av_thread_message_queue_alloc(&f->in_thread_queue,
- 8, sizeof(AVPacket));
+ qs, sizeof(AVPacket));
if (ret < 0)
return ret;
--
2.1.4
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