mpeg12: raise timecode to codec context.

libavcodec/avcodec.h

@@ -2710,9 +2710,9 @@ typedef struct AVCodecContext {
 #endif
 
     /**
-     * GOP timecode frame start number, in non drop frame format
-     * - encoding: Set by user.
-     * - decoding: unused
+     * GOP timecode frame start number
+     * - encoding: Set by user, in non drop frame format
+     * - decoding: Set by libavcodec (timecode in the 25 bits format, -1 if unset)
      */
     int64_t timecode_frame_start;
 

libavcodec/mpeg12.c

@@ -2141,20 +2141,12 @@ static void mpeg_decode_gop(AVCodecContext *avctx,
 {
     Mpeg1Context *s1  = avctx->priv_data;
     MpegEncContext *s = &s1->mpeg_enc_ctx;
-
-    int drop_frame_flag;
-    int time_code_hours, time_code_minutes;
-    int time_code_seconds, time_code_pictures;
     int broken_link;
+    int64_t tc;
 
     init_get_bits(&s->gb, buf, buf_size*8);
 
-    drop_frame_flag   = get_bits(&s->gb, 1);
-    time_code_hours   = get_bits(&s->gb, 5);
-    time_code_minutes = get_bits(&s->gb, 6);
-    skip_bits1(&s->gb); // marker bit
-    time_code_seconds  = get_bits(&s->gb, 6);
-    time_code_pictures = get_bits(&s->gb, 6);
+    tc = avctx->timecode_frame_start = get_bits(&s->gb, 25);
 
     s->closed_gop = get_bits1(&s->gb);
     /*broken_link indicate that after editing the
@@ -2162,11 +2154,17 @@ static void mpeg_decode_gop(AVCodecContext *avctx,
       are missing (open gop)*/
     broken_link = get_bits1(&s->gb);
 
-    if (s->avctx->debug & FF_DEBUG_PICT_INFO)
+    if (s->avctx->debug & FF_DEBUG_PICT_INFO) {
+        int time_code_hours    = tc>>19 & 0x1f;
+        int time_code_minutes  = tc>>13 & 0x3f;
+        int time_code_seconds  = tc>>6  & 0x3f;
+        int drop_frame_flag    = tc     & 1<<24;
+        int time_code_pictures = tc     & 0x3f;
         av_log(s->avctx, AV_LOG_DEBUG, "GOP (%02d:%02d:%02d%c%02d) closed_gop=%d broken_link=%d\n",
                time_code_hours, time_code_minutes, time_code_seconds,
                drop_frame_flag ? ';' : ':',
                time_code_pictures, s->closed_gop, broken_link);
+    }
 }
 /**
  * Find the end of the current frame in the bitstream.

libavcodec/mpeg12enc.c

@@ -185,6 +185,8 @@ static av_cold int encode_init(AVCodecContext *avctx)
         if (ff_init_smtpe_timecode(s, &s->tc) < 0)
             return -1;
         s->avctx->timecode_frame_start = s->tc.start;
+    } else {
+        s->avctx->timecode_frame_start = 0; // default is -1
     }
     return 0;
 }

libavcodec/options.c

@@ -578,6 +578,7 @@ int avcodec_get_context_defaults3(AVCodecContext *s, AVCodec *codec){
     s->sample_aspect_ratio = (AVRational){0,1};
     s->pix_fmt             = PIX_FMT_NONE;
     s->sample_fmt          = AV_SAMPLE_FMT_NONE;
+    s->timecode_frame_start = -1;
 
     s->reget_buffer        = avcodec_default_reget_buffer;
     s->reordered_opaque    = AV_NOPTS_VALUE;

libavcodec/version.h

@@ -21,7 +21,7 @@
 #define AVCODEC_VERSION_H
 
 #define LIBAVCODEC_VERSION_MAJOR 53
-#define LIBAVCODEC_VERSION_MINOR 38
+#define LIBAVCODEC_VERSION_MINOR 39
 #define LIBAVCODEC_VERSION_MICRO  1
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \