fftools/ffmpeg: convert timestamps inside the muxer

Packets submitted to the muxer now have their timebase attached to them,
so the muxer can do conversion to muxing timebase and avoid exposing it
to callers.

fftools/ffmpeg_enc.c

@@ -512,8 +512,8 @@ void enc_subtitle(OutputFile *of, OutputStream *ost, AVSubtitle *sub)
         }
 
         av_shrink_packet(pkt, subtitle_out_size);
-        pkt->time_base = ost->mux_timebase;
-        pkt->pts  = av_rescale_q(sub->pts, AV_TIME_BASE_Q, pkt->time_base);
+        pkt->time_base = AV_TIME_BASE_Q;
+        pkt->pts       = sub->pts;
         pkt->duration = av_rescale_q(sub->end_display_time, (AVRational){ 1, 1000 }, pkt->time_base);
         if (enc->codec_id == AV_CODEC_ID_DVB_SUBTITLE) {
             /* XXX: the pts correction is handled here. Maybe handling
@@ -735,19 +735,6 @@ static int encode_frame(OutputFile *of, OutputStream *ost, AVFrame *frame)
                    av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, &enc->time_base));
         }
 
-        av_packet_rescale_ts(pkt, pkt->time_base, ost->mux_timebase);
-        pkt->time_base = ost->mux_timebase;
-
-        if (debug_ts) {
-            av_log(ost, AV_LOG_INFO, "encoder -> type:%s "
-                   "pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s "
-                   "duration:%s duration_time:%s\n",
-                   type_desc,
-                   av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &enc->time_base),
-                   av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &enc->time_base),
-                   av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, &enc->time_base));
-        }
-
         if ((ret = trigger_fix_sub_duration_heartbeat(ost, pkt)) < 0) {
             av_log(NULL, AV_LOG_ERROR,
                    "Subtitle heartbeat logic failed in %s! (%s)\n",

fftools/ffmpeg_mux.c

@@ -334,6 +334,12 @@ void of_output_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int eof)
     if (!eof && pkt->dts != AV_NOPTS_VALUE)
         ost->last_mux_dts = av_rescale_q(pkt->dts, pkt->time_base, AV_TIME_BASE_Q);
 
+    /* rescale timestamps to the muxing timebase */
+    if (!eof) {
+        av_packet_rescale_ts(pkt, pkt->time_base, ost->mux_timebase);
+        pkt->time_base = ost->mux_timebase;
+    }
+
     /* apply the output bitstream filters */
     if (ms->bsf_ctx) {
         int bsf_eof = 0;