gifdec: do not handle timestamps

It is broken, and results will be messed up when seeking.

This also fix duration displayed for streams when using -c copy.
Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/gifdec.c

@@ -44,8 +44,6 @@ typedef struct GIFDemuxContext {
      */
     int min_delay;
     int default_delay;
-    int total_duration; ///< In hundredths of second.
-    int frame_idx;
 } GIFDemuxContext;
 
 /**
@@ -190,9 +188,6 @@ static int gif_read_packet(AVFormatContext *s, AVPacket *pkt)
             if ((ret = avio_skip(pb, ct_size)) < 0)
                 return ret;
         }
-
-        gdc->total_duration = 0;
-        gdc->frame_idx      = 0;
     } else {
         avio_seek(pb, -ret, SEEK_CUR);
         ret = AVERROR_EOF;
@@ -239,15 +234,11 @@ static int gif_read_packet(AVFormatContext *s, AVPacket *pkt)
                 pkt->flags |= AV_PKT_FLAG_KEY;
 
             pkt->stream_index = 0;
-            pkt->pts = gdc->total_duration;
-            gdc->total_duration += gdc->delay;
             pkt->duration = gdc->delay;
-            pkt->dts = gdc->frame_idx;
 
             /* Graphic Control Extension's scope is single frame.
              * Remove its influence. */
             gdc->delay = gdc->default_delay;
-            gdc->frame_idx++;
             frame_parsed = 1;
 
             break;

tests/ref/lavf/gif

 e6089fd4ef3b9df44090ab3650bdd810 *./tests/data/lavf/lavf.gif
 2906401 ./tests/data/lavf/lavf.gif
-./tests/data/lavf/lavf.gif CRC=0xbf89a246
+./tests/data/lavf/lavf.gif CRC=0x9825d7c0
 022dc66b5068404e88c618ce79d9eb5f *./tests/data/images/gif/02.gif
 ./tests/data/images/gif/%02d.gif CRC=0x032e0034
 81538 ./tests/data/images/gif/02.gif