fftools/ffmpeg: attach InputStream.dts to demuxed packets when needed

This way computing it and using it for streamcopy does not need to
happen in sync. Will be useful in following commits, where updating
InputStream.dts will be moved to the demuxing thread.

fftools/ffmpeg.c

@@ -1368,6 +1368,7 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
 {
     InputFile *f = input_files[ist->file_index];
     const AVCodecParameters *par = ist->par;
+    int64_t dts_est = AV_NOPTS_VALUE;
     int ret = 0;
     int repeating = 0;
     int eof_reached = 0;
@@ -1463,6 +1464,11 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
     if (!pkt && !ist->decoding_needed)
         eof_reached = 1;
 
+    if (pkt && pkt->opaque_ref) {
+        DemuxPktData *pd = (DemuxPktData*)pkt->opaque_ref->data;
+        dts_est = pd->dts_est;
+    }
+
     duration_exceeded = 0;
     if (f->recording_time != INT64_MAX) {
         int64_t start_time = 0;
@@ -1470,7 +1476,7 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
             start_time += f->start_time != AV_NOPTS_VALUE ? f->start_time : 0;
             start_time += start_at_zero ? 0 : f->start_time_effective;
         }
-        if (ist->dts >= f->recording_time + start_time)
+        if (dts_est >= f->recording_time + start_time)
             duration_exceeded = 1;
     }
 
@@ -1484,7 +1490,7 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
             continue;
         }
 
-        of_streamcopy(ost, pkt, ist->dts);
+        of_streamcopy(ost, pkt, dts_est);
     }
 
     return !eof_reached;
@@ -1900,6 +1906,18 @@ static void ist_dts_update(InputStream *ist, AVPacket *pkt)
         }
         break;
     }
+
+    av_assert0(!pkt->opaque_ref);
+    if (ist->streamcopy_needed) {
+        DemuxPktData *pd;
+
+        pkt->opaque_ref = av_buffer_allocz(sizeof(*pd));
+        if (!pkt->opaque_ref)
+            report_and_exit(AVERROR(ENOMEM));
+        pd = (DemuxPktData*)pkt->opaque_ref->data;
+
+        pd->dts_est = ist->dts;
+    }
 }
 
 /*

fftools/ffmpeg.h

@@ -95,6 +95,12 @@ typedef struct {
 } AudioChannelMap;
 #endif
 
+typedef struct DemuxPktData {
+    // estimated dts in AV_TIME_BASE_Q,
+    // to be used when real dts is missing
+    int64_t dts_est;
+} DemuxPktData;
+
 typedef struct OptionsContext {
     OptionGroup *g;
 
@@ -337,6 +343,7 @@ typedef struct InputStream {
     int discard;             /* true if stream data should be discarded */
     int user_set_discard;
     int decoding_needed;     /* non zero if the packets must be decoded in 'raw_fifo', see DECODING_FOR_* */
+    int streamcopy_needed;
 #define DECODING_FOR_OST    1
 #define DECODING_FOR_FILTER 2
     // should attach FrameData as opaque_ref after decoding

fftools/ffmpeg_demux.c

@@ -584,6 +584,7 @@ static void ist_use(InputStream *ist, int decoding_needed)
     ist->discard          = 0;
     ist->st->discard      = ist->user_set_discard;
     ist->decoding_needed |= decoding_needed;
+    ist->streamcopy_needed |= !decoding_needed;
 
     if (decoding_needed && !avcodec_is_open(ist->dec_ctx)) {
         int ret = dec_open(ist);