ffmpeg: fix accurate seeking with -copyts

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

ffmpeg.h

@@ -483,6 +483,7 @@ extern int do_deinterlace;
 extern int do_hex_dump;
 extern int do_pkt_dump;
 extern int copy_ts;
+extern int start_at_zero;
 extern int copy_tb;
 extern int debug_ts;
 extern int exit_on_error;

ffmpeg_filter.c

@@ -637,6 +637,7 @@ static int configure_input_video_filter(FilterGraph *fg, InputFilter *ifilter,
     AVBPrint args;
     char name[255];
     int ret, pad_idx = 0;
+    int64_t tsoffset = 0;
 
     if (ist->dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
         av_log(NULL, AV_LOG_ERROR, "Cannot connect video filter to audio input\n");
@@ -711,8 +712,14 @@ static int configure_input_video_filter(FilterGraph *fg, InputFilter *ifilter,
 
     snprintf(name, sizeof(name), "trim for input stream %d:%d",
              ist->file_index, ist->st->index);
+    if (copy_ts) {
+        tsoffset = f->start_time == AV_NOPTS_VALUE ? 0 : f->start_time;
+        if (!start_at_zero && f->ctx->start_time != AV_NOPTS_VALUE)
+            tsoffset += f->ctx->start_time;
+    }
     ret = insert_trim(((f->start_time == AV_NOPTS_VALUE) || !f->accurate_seek) ?
-                      AV_NOPTS_VALUE : 0, f->recording_time, &last_filter, &pad_idx, name);
+                      AV_NOPTS_VALUE : tsoffset, f->recording_time,
+                      &last_filter, &pad_idx, name);
     if (ret < 0)
         return ret;
 
@@ -731,6 +738,7 @@ static int configure_input_audio_filter(FilterGraph *fg, InputFilter *ifilter,
     AVBPrint args;
     char name[255];
     int ret, pad_idx = 0;
+    int64_t tsoffset = 0;
 
     if (ist->dec_ctx->codec_type != AVMEDIA_TYPE_AUDIO) {
         av_log(NULL, AV_LOG_ERROR, "Cannot connect audio filter to non audio input\n");
@@ -813,8 +821,14 @@ static int configure_input_audio_filter(FilterGraph *fg, InputFilter *ifilter,
 
     snprintf(name, sizeof(name), "trim for input stream %d:%d",
              ist->file_index, ist->st->index);
+    if (copy_ts) {
+        tsoffset = f->start_time == AV_NOPTS_VALUE ? 0 : f->start_time;
+        if (!start_at_zero && f->ctx->start_time != AV_NOPTS_VALUE)
+            tsoffset += f->ctx->start_time;
+    }
     ret = insert_trim(((f->start_time == AV_NOPTS_VALUE) || !f->accurate_seek) ?
-                      AV_NOPTS_VALUE : 0, f->recording_time, &last_filter, &pad_idx, name);
+                      AV_NOPTS_VALUE : tsoffset, f->recording_time,
+                      &last_filter, &pad_idx, name);
     if (ret < 0)
         return ret;