ffmpeg | branch: release/2.2 | Timothy B. Terriberry <tterr...@xiph.org> | Mon Oct 13 17:46:00 2014 -0700| [72ed4166a64714952777fb028b546a52e5b4e2c2] | committer: Anton Khirnov
resample: Avoid off-by-1 errors in PTS calcs. The rounding used in the PTS calculations in filter_frame() does not actually match the number of samples output by the resampler. This leads to off-by-1 errors in the timestamps indicating gaps and underruns, even when the input timestamps are all contiguous. Bug-Id: 753 Signed-off-by: Anton Khirnov <an...@khirnov.net> (cherry picked from commit 6cbbf0592f4f3940aac7f687850d1b726a2ea836) Signed-off-by: Anton Khirnov <an...@khirnov.net> (cherry picked from commit ca8c62d187fdca13979379fb2ab172ed662aa2f8) Signed-off-by: Anton Khirnov <an...@khirnov.net> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=72ed4166a64714952777fb028b546a52e5b4e2c2 --- libavfilter/af_resample.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/libavfilter/af_resample.c b/libavfilter/af_resample.c index a89ab35..83c27b5 100644 --- a/libavfilter/af_resample.c +++ b/libavfilter/af_resample.c @@ -42,6 +42,7 @@ typedef struct ResampleContext { AVDictionary *options; int64_t next_pts; + int64_t next_in_pts; /* set by filter_frame() to signal an output frame to request_frame() */ int got_output; @@ -154,6 +155,7 @@ static int config_output(AVFilterLink *outlink) outlink->time_base = (AVRational){ 1, outlink->sample_rate }; s->next_pts = AV_NOPTS_VALUE; + s->next_in_pts = AV_NOPTS_VALUE; av_get_channel_layout_string(buf1, sizeof(buf1), -1, inlink ->channel_layout); @@ -260,7 +262,12 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in) } out->sample_rate = outlink->sample_rate; - if (in->pts != AV_NOPTS_VALUE) { + /* Only convert in->pts if there is a discontinuous jump. + This ensures that out->pts tracks the number of samples actually + output by the resampler in the absence of such a jump. + Otherwise, the rounding in av_rescale_q() and av_rescale() + causes off-by-1 errors. */ + if (in->pts != AV_NOPTS_VALUE && in->pts != s->next_in_pts) { out->pts = av_rescale_q(in->pts, inlink->time_base, outlink->time_base) - av_rescale(delay, outlink->sample_rate, @@ -269,6 +276,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in) out->pts = s->next_pts; s->next_pts = out->pts + out->nb_samples; + s->next_in_pts = in->pts + in->nb_samples; ret = ff_filter_frame(outlink, out); s->got_output = 1; _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog
