[FFmpeg-cvslog] mpeg12dec: Extract CC user data into frame side data
John Stebbins
git at videolan.org
Tue Nov 26 13:11:16 CET 2013
ffmpeg | branch: master | John Stebbins <stebbins at jetheaddev.com> | Mon Nov 25 15:57:28 2013 -0800| [1eaac1d6f7bb8e52d82e1a114c88a59a9a8e5025] | committer: Anton Khirnov
mpeg12dec: Extract CC user data into frame side data
Signed-off-by: Anton Khirnov <anton at khirnov.net>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1eaac1d6f7bb8e52d82e1a114c88a59a9a8e5025
---
doc/APIchanges | 4 +++
libavcodec/mpeg12dec.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++
libavutil/frame.h | 6 +++++
libavutil/version.h | 2 +-
4 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/doc/APIchanges b/doc/APIchanges
index 1882fb8..1e380e9 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -13,6 +13,10 @@ libavutil: 2012-10-22
API changes, most recent first:
+2013-11-xx - xxxxxxx- - lavu 52.19.0 - frame.h
+ Add AV_FRAME_DATA_A53_CC value to the AVFrameSideDataType enum, which
+ identifies ATSC A53 Part 4 Closed Captions data.
+
2013-11-xx - xxxxxxx - lavu 52.18.0 - mem.h
Move av_fast_malloc() and av_fast_realloc() for libavcodec to libavutil.
diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 0e11dda..9d0c3be 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -44,6 +44,8 @@ typedef struct Mpeg1Context {
int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
int repeat_field; /* true if we must repeat the field */
AVPanScan pan_scan; /**< some temporary storage for the panscan */
+ uint8_t *a53_caption;
+ int a53_caption_size;
int slice_count;
int save_aspect_info;
int save_width, save_height, save_progressive_seq;
@@ -1529,6 +1531,14 @@ static int mpeg_field_start(MpegEncContext *s, const uint8_t *buf, int buf_size)
return AVERROR(ENOMEM);
memcpy(pan_scan->data, &s1->pan_scan, sizeof(s1->pan_scan));
+ if (s1->a53_caption) {
+ AVFrameSideData *sd = av_frame_new_side_data(
+ &s->current_picture_ptr->f, AV_FRAME_DATA_A53_CC,
+ s1->a53_caption_size);
+ if (sd)
+ memcpy(sd->data, s1->a53_caption, s1->a53_caption_size);
+ av_freep(&s1->a53_caption);
+ }
if (HAVE_THREADS && (avctx->active_thread_type & FF_THREAD_FRAME))
ff_thread_finish_setup(avctx);
} else { // second field
@@ -2038,6 +2048,60 @@ static int vcr2_init_sequence(AVCodecContext *avctx)
}
+static int mpeg_decode_a53_cc(AVCodecContext *avctx,
+ const uint8_t *p, int buf_size)
+{
+ Mpeg1Context *s1 = avctx->priv_data;
+
+ if (buf_size >= 6 &&
+ p[0] == 'G' && p[1] == 'A' && p[2] == '9' && p[3] == '4' &&
+ p[4] == 3 && (p[5] & 0x40)) {
+ /* extract A53 Part 4 CC data */
+ int cc_count = p[5] & 0x1f;
+ if (cc_count > 0 && buf_size >= 7 + cc_count * 3) {
+ av_freep(&s1->a53_caption);
+ s1->a53_caption_size = cc_count * 3;
+ s1->a53_caption = av_malloc(s1->a53_caption_size);
+ if (s1->a53_caption) {
+ memcpy(s1->a53_caption, p + 7, s1->a53_caption_size);
+ }
+ }
+ return 1;
+ } else if (buf_size >= 11 &&
+ p[0] == 'C' && p[1] == 'C' && p[2] == 0x01 && p[3] == 0xf8) {
+ /* extract DVD CC data */
+ int cc_count = 0;
+ int i;
+ // There is a caption count field in the data, but it is often
+ // incorect. So count the number of captions present.
+ for (i = 5; i + 6 <= buf_size && ((p[i] & 0xfe) == 0xfe); i += 6)
+ cc_count++;
+ // Transform the DVD format into A53 Part 4 format
+ if (cc_count > 0) {
+ av_freep(&s1->a53_caption);
+ s1->a53_caption_size = cc_count * 6;
+ s1->a53_caption = av_malloc(s1->a53_caption_size);
+ if (s1->a53_caption) {
+ uint8_t field1 = !!(p[4] & 0x80);
+ uint8_t *cap = s1->a53_caption;
+ p += 5;
+ for (i = 0; i < cc_count; i++) {
+ cap[0] = (p[0] == 0xff && field1) ? 0xfc : 0xfd;
+ cap[1] = p[1];
+ cap[2] = p[2];
+ cap[3] = (p[3] == 0xff && !field1) ? 0xfc : 0xfd;
+ cap[4] = p[4];
+ cap[5] = p[5];
+ cap += 6;
+ p += 6;
+ }
+ }
+ }
+ return 1;
+ }
+ return 0;
+}
+
static void mpeg_decode_user_data(AVCodecContext *avctx,
const uint8_t *p, int buf_size)
{
@@ -2057,6 +2121,8 @@ static void mpeg_decode_user_data(AVCodecContext *avctx,
return;
avctx->dtg_active_format = p[0] & 0x0f;
}
+ } else if (mpeg_decode_a53_cc(avctx, p, buf_size)) {
+ return;
}
}
@@ -2402,6 +2468,7 @@ static av_cold int mpeg_decode_end(AVCodecContext *avctx)
if (s->mpeg_enc_ctx_allocated)
ff_MPV_common_end(&s->mpeg_enc_ctx);
+ av_freep(&s->a53_caption);
return 0;
}
diff --git a/libavutil/frame.h b/libavutil/frame.h
index 449a6b7..d869d83 100644
--- a/libavutil/frame.h
+++ b/libavutil/frame.h
@@ -35,6 +35,12 @@ enum AVFrameSideDataType {
* The data is the AVPanScan struct defined in libavcodec.
*/
AV_FRAME_DATA_PANSCAN,
+ /**
+ * ATSC A53 Part 4 Closed Captions.
+ * A53 CC bitstream is stored as uint8_t in AVFrameSideData.data.
+ * The number of bytes of CC data is AVFrameSideData.size.
+ */
+ AV_FRAME_DATA_A53_CC,
};
typedef struct AVFrameSideData {
diff --git a/libavutil/version.h b/libavutil/version.h
index 4f0f469..fa1f53b 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -37,7 +37,7 @@
*/
#define LIBAVUTIL_VERSION_MAJOR 52
-#define LIBAVUTIL_VERSION_MINOR 18
+#define LIBAVUTIL_VERSION_MINOR 19
#define LIBAVUTIL_VERSION_MICRO 0
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
More information about the ffmpeg-cvslog
mailing list