[FFmpeg-devel] [PATCH] avfilter/af_atempo: offset all output timestamps by same amount of first input timestamp

[Paul B Mahol]

Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
Makes ffplay display correct timestamps when seeking.
---
 libavfilter/af_atempo.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libavfilter/af_atempo.c b/libavfilter/af_atempo.c
index bfdad7d76b..6a23d59641 100644
--- a/libavfilter/af_atempo.c
+++ b/libavfilter/af_atempo.c
@@ -103,6 +103,9 @@ typedef struct ATempoContext {
     // 1: output sample position
     int64_t position[2];
 
+    // first input timestamp, all other timestamps are offset by this one
+    int64_t start_pts;
+
     // sample format:
     enum AVSampleFormat format;
 
@@ -1055,6 +1058,7 @@ static int config_props(AVFilterLink *inlink)
     enum AVSampleFormat format = inlink->format;
     int sample_rate = (int)inlink->sample_rate;
 
+    atempo->start_pts = AV_NOPTS_VALUE;
     return yae_reset(atempo, format, sample_rate, inlink->channels);
 }
 
@@ -1068,7 +1072,7 @@ static int push_samples(ATempoContext *atempo,
     atempo->dst_buffer->nb_samples  = n_out;
 
     // adjust the PTS:
-    atempo->dst_buffer->pts =
+    atempo->dst_buffer->pts = atempo->start_pts +
         av_rescale_q(atempo->nsamples_out,
                      (AVRational){ 1, outlink->sample_rate },
                      outlink->time_base);
@@ -1097,6 +1101,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *src_buffer)
     const uint8_t *src = src_buffer->data[0];
     const uint8_t *src_end = src + n_in * atempo->stride;
 
+    if (atempo->start_pts == AV_NOPTS_VALUE)
+        atempo->start_pts = src_buffer->pts;
     while (src < src_end) {
         if (!atempo->dst_buffer) {
             atempo->dst_buffer = ff_get_audio_buffer(outlink, n_out);
-- 
2.17.1