[FFmpeg-devel] [PATCH]Tell users about Closed Captions in video streams

Carl Eugen Hoyos cehoyos at ag.or.at
Mon Jul 6 17:53:29 CEST 2015


Hi!

Attached patch adds "Closed Captions" to the codec dump if 
the video stream contains them.

Please comment, Carl Eugen
-------------- next part --------------
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index e367399..c39a241 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3171,6 +3171,14 @@ typedef struct AVCodecContext {
      * - decoding: set by user through AVOPtions (NO direct access)
      */
     char *codec_whitelist;
+
+    /**
+     * Set if the (video) stream contains internal Closed Captions
+     * Not to be accessed outside of libavcodec
+     * - encoding: unused
+     * - decoding: set by libavcodec
+     */
+    int closed_captions;
 } AVCodecContext;
 
 AVRational av_codec_get_pkt_timebase         (const AVCodecContext *avctx);
diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index f62ad6a..824abd6 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -886,6 +886,7 @@ static void decode_postinit(H264Context *h, int setup_finished)
             memcpy(sd->data, h->a53_caption, h->a53_caption_size);
         av_freep(&h->a53_caption);
         h->a53_caption_size = 0;
+        h->avctx->closed_captions = 1;
     }
 
     cur->mmco_reset = h->mmco_reset;
diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index b0e5ae9..c250d55 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -1685,6 +1685,7 @@ static int mpeg_field_start(MpegEncContext *s, const uint8_t *buf, int buf_size)
             if (sd)
                 memcpy(sd->data, s1->a53_caption, s1->a53_caption_size);
             av_freep(&s1->a53_caption);
+            avctx->closed_captions = 1;
         }
 
         if (s1->has_stereo3d) {
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index b80b4e7..26b1662 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -3136,6 +3136,10 @@ void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode)
         if (encode) {
             snprintf(buf + strlen(buf), buf_size - strlen(buf),
                      ", q=%d-%d", enc->qmin, enc->qmax);
+        } else {
+            if (enc->closed_captions)
+                snprintf(buf + strlen(buf), buf_size - strlen(buf),
+                     ", Closed Captions");
         }
         break;
     case AVMEDIA_TYPE_AUDIO:


More information about the ffmpeg-devel mailing list