Hi
This is basic implementation where all features of closed caption are
not implemented.
-Anshul
>From 09a199afa72eeb7b8be8527da7239f4abcc52dbe Mon Sep 17 00:00:00 2001
From: Nicolas George <geo...@nsup.org>
Date: Tue, 28 Oct 2014 14:41:15 +0530
Subject: [PATCH 1/2] allow to extract subcc
---
doc/indevs.texi | 9 ++++++
libavdevice/lavfi.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++----
2 files changed, 84 insertions(+), 5 deletions(-)
diff --git a/doc/indevs.texi b/doc/indevs.texi
index 5d2a308..f31e2e3 100644
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -494,6 +494,9 @@ number starting from 0 corresponding to the mapped input stream
generated by the device.
The first unlabelled output is automatically assigned to the "out0"
label, but all the others need to be specified explicitly.
+The suffix "+subcc" can be appended to the output label to create an extra
+stream with the closed captions packets attached to that output
+(experimental).
If not specified defaults to the filename specified for the input
device.
@@ -541,6 +544,12 @@ Read an audio stream and a video stream and play it back with
ffplay -f lavfi "movie=test.avi[out0];amovie=test.wav[out1]"
@end example
+@item
+Dump decoded frames to images and closed captions to a file (experimental):
+@example
+ffmpeg -f lavfi -i "movie=test.ts[out0+subcc]" -map v frame%08d.png -map s -c copy -f rawvideo subcc.bin
+@end example
+
@end itemize
@section libcdio
diff --git a/libavdevice/lavfi.c b/libavdevice/lavfi.c
index 1398ece..bc45117 100644
--- a/libavdevice/lavfi.c
+++ b/libavdevice/lavfi.c
@@ -51,7 +51,10 @@ typedef struct {
int *sink_stream_map;
int *sink_eof;
int *stream_sink_map;
+ int *sink_stream_subcc_map;
AVFrame *decoded_frame;
+ int nb_sinks;
+ AVPacket subcc_packet;
} LavfiContext;
static int *create_all_formats(int n)
@@ -82,6 +85,7 @@ av_cold static int lavfi_read_close(AVFormatContext *avctx)
av_freep(&lavfi->sink_stream_map);
av_freep(&lavfi->sink_eof);
av_freep(&lavfi->stream_sink_map);
+ av_freep(&lavfi->sink_stream_subcc_map);
av_freep(&lavfi->sinks);
avfilter_graph_free(&lavfi->graph);
av_frame_free(&lavfi->decoded_frame);
@@ -89,6 +93,27 @@ av_cold static int lavfi_read_close(AVFormatContext *avctx)
return 0;
}
+static int create_subcc_streams(AVFormatContext *avctx)
+{
+ LavfiContext *lavfi = avctx->priv_data;
+ AVStream *st;
+ int stream_idx, sink_idx;
+
+ for (stream_idx = 0; stream_idx < lavfi->nb_sinks; stream_idx++) {
+ sink_idx = lavfi->stream_sink_map[stream_idx];
+ if (lavfi->sink_stream_subcc_map[sink_idx]) {
+ lavfi->sink_stream_subcc_map[sink_idx] = avctx->nb_streams;
+ if (!(st = avformat_new_stream(avctx, NULL)))
+ return AVERROR(ENOMEM);
+ st->codec->codec_id = AV_CODEC_ID_EIA_608;
+ st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
+ } else {
+ lavfi->sink_stream_subcc_map[sink_idx] = -1;
+ }
+ }
+ return 0;
+}
+
av_cold static int lavfi_read_header(AVFormatContext *avctx)
{
LavfiContext *lavfi = avctx->priv_data;
@@ -153,6 +178,7 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
/* count the outputs */
for (n = 0, inout = output_links; inout; n++, inout = inout->next);
+ lavfi->nb_sinks = n;
if (!(lavfi->sink_stream_map = av_malloc(sizeof(int) * n)))
FAIL(AVERROR(ENOMEM));
@@ -160,6 +186,8 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
FAIL(AVERROR(ENOMEM));
if (!(lavfi->stream_sink_map = av_malloc(sizeof(int) * n)))
FAIL(AVERROR(ENOMEM));
+ if (!(lavfi->sink_stream_subcc_map = av_malloc(sizeof(int) * n)))
+ FAIL(AVERROR(ENOMEM));
for (i = 0; i < n; i++)
lavfi->stream_sink_map[i] = -1;
@@ -167,10 +195,10 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
/* parse the output link names - they need to be of the form out0, out1, ...
* create a mapping between them and the streams */
for (i = 0, inout = output_links; inout; i++, inout = inout->next) {
- int stream_idx;
+ int stream_idx, use_subcc = 0;
if (!strcmp(inout->name, "out"))
stream_idx = 0;
- else if (sscanf(inout->name, "out%d\n", &stream_idx) != 1) {
+ else if (sscanf(inout->name, "out%d+subcc%n\n", &stream_idx, &use_subcc) != 1) {
av_log(avctx, AV_LOG_ERROR,
"Invalid outpad name '%s'\n", inout->name);
FAIL(AVERROR(EINVAL));
@@ -192,6 +220,7 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
}
lavfi->sink_stream_map[i] = stream_idx;
lavfi->stream_sink_map[stream_idx] = i;
+ lavfi->sink_stream_subcc_map[stream_idx] = !!use_subcc;
}
/* for each open output create a corresponding stream */
@@ -203,7 +232,7 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
}
/* create a sink for each output and connect them to the graph */
- lavfi->sinks = av_malloc_array(avctx->nb_streams, sizeof(AVFilterContext *));
+ lavfi->sinks = av_malloc_array(lavfi->nb_sinks, sizeof(AVFilterContext *));
if (!lavfi->sinks)
FAIL(AVERROR(ENOMEM));
@@ -267,7 +296,7 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
}
/* fill each stream with the information in the corresponding sink */
- for (i = 0; i < avctx->nb_streams; i++) {
+ for (i = 0; i < lavfi->nb_sinks; i++) {
AVFilterLink *link = lavfi->sinks[lavfi->stream_sink_map[i]]->inputs[0];
AVStream *st = avctx->streams[i];
st->codec->codec_type = link->type;
@@ -298,6 +327,9 @@ av_cold static int lavfi_read_header(AVFormatContext *avctx)
}
}
+ if ((ret = create_subcc_streams(avctx)) < 0)
+ FAIL(ret);
+
if (!(lavfi->decoded_frame = av_frame_alloc()))
FAIL(AVERROR(ENOMEM));
@@ -310,6 +342,30 @@ end:
return ret;
}
+static int create_subcc_packet(AVFormatContext *avctx, AVFrame *frame,
+ int sink_idx)
+{
+ LavfiContext *lavfi = avctx->priv_data;
+ AVFrameSideData *sd;
+ int stream_idx, i, ret;
+
+ if ((stream_idx = lavfi->sink_stream_subcc_map[sink_idx]) < 0)
+ return 0;
+ for (i = 0; i < frame->nb_side_data; i++)
+ if (frame->side_data[i]->type == AV_FRAME_DATA_A53_CC)
+ break;
+ if (i >= frame->nb_side_data)
+ return 0;
+ sd = frame->side_data[i];
+ if ((ret = av_new_packet(&lavfi->subcc_packet, sd->size)) < 0)
+ return ret;
+ memcpy(lavfi->subcc_packet.data, sd->data, sd->size);
+ lavfi->subcc_packet.stream_index = stream_idx;
+ lavfi->subcc_packet.pts = frame->pts;
+ lavfi->subcc_packet.pos = av_frame_get_pkt_pos(frame);
+ return 0;
+}
+
static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
{
LavfiContext *lavfi = avctx->priv_data;
@@ -321,9 +377,17 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
int ret, i;
int size = 0;
+ if (lavfi->subcc_packet.size) {
+ *pkt = lavfi->subcc_packet;
+ av_init_packet(&lavfi->subcc_packet);
+ lavfi->subcc_packet.size = 0;
+ lavfi->subcc_packet.data = NULL;
+ return pkt->size;
+ }
+
/* iterate through all the graph sinks. Select the sink with the
* minimum PTS */
- for (i = 0; i < avctx->nb_streams; i++) {
+ for (i = 0; i < lavfi->nb_sinks; i++) {
AVRational tb = lavfi->sinks[i]->inputs[0]->time_base;
double d;
int ret;
@@ -397,6 +461,12 @@ static int lavfi_read_packet(AVFormatContext *avctx, AVPacket *pkt)
av_bprint_finalize(&meta_buf, NULL);
}
+ if ((ret = create_subcc_packet(avctx, frame, min_pts_sink_idx)) < 0) {
+ av_frame_unref(frame);
+ av_packet_unref(pkt);
+ return ret;
+ }
+
pkt->stream_index = stream_idx;
pkt->pts = frame->pts;
pkt->pos = av_frame_get_pkt_pos(frame);
--
1.8.1.4
>From 1e52ce4b9b47f0cc630cfaee783ea0f44e212476 Mon Sep 17 00:00:00 2001
From: Anshul Maheshwari <anshul.ffm...@gmail.com>
Date: Mon, 1 Dec 2014 22:25:04 +0530
Subject: [PATCH 2/2] Adding closed caption decoder
---
libavcodec/Makefile | 1 +
libavcodec/allcodecs.c | 1 +
libavcodec/ccaption_dec.c | 243 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 245 insertions(+)
create mode 100644 libavcodec/ccaption_dec.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index fa0f53d..bbc516d 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -173,6 +173,7 @@ OBJS-$(CONFIG_BRENDER_PIX_DECODER) += brenderpix.o
OBJS-$(CONFIG_C93_DECODER) += c93.o
OBJS-$(CONFIG_CAVS_DECODER) += cavs.o cavsdec.o cavsdsp.o \
cavsdata.o mpeg12data.o
+OBJS-$(CONFIG_CCAPTION_DECODER) += ccaption_dec.o
OBJS-$(CONFIG_CDGRAPHICS_DECODER) += cdgraphics.o
OBJS-$(CONFIG_CDXL_DECODER) += cdxl.o
OBJS-$(CONFIG_CINEPAK_DECODER) += cinepak.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 0d39d33..8c07388 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -480,6 +480,7 @@ void avcodec_register_all(void)
/* subtitles */
REGISTER_ENCDEC (SSA, ssa);
REGISTER_ENCDEC (ASS, ass);
+ REGISTER_DECODER(CCAPTION, ccaption);
REGISTER_ENCDEC (DVBSUB, dvbsub);
REGISTER_ENCDEC (DVDSUB, dvdsub);
REGISTER_DECODER(JACOSUB, jacosub);
diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
new file mode 100644
index 0000000..a665f64
--- /dev/null
+++ b/libavcodec/ccaption_dec.c
@@ -0,0 +1,243 @@
+#include "avcodec.h"
+#include "libavcodec/ass.h"
+
+typedef struct CCaptionSubContext {
+ int parity_table[256];
+ int row_cnt;
+ char *buffer;
+ int index;
+ int data_len;
+ int buf_len;
+ /* erase display memory */
+ int edm;
+ int rollup;
+ int64_t start_time;
+ int64_t end_time;
+ char prev_cmd[2];
+}CCaptionSubContext;
+
+static unsigned int av_always_inline is_oddparity1p7(unsigned int val)
+{
+//#if defined(__x86_64__) || defined(_M_X64) || defined(__i386) || defined(_M_IX86)
+#if 0
+ asm goto (
+ "and $0x7F, %0\n\t"
+ "jnp %l1 \n\t"
+ :/* no output */
+ :"r"(val)
+ :"cc"
+ :odd
+ );
+ val = !(val&0x8);
+odd:
+ val = !!(val&0x80);
+#else
+ int ones = 0;
+ int i = 0;
+
+ for (i = 0; i < 7; i++) {
+ if (val & (1 << i))
+ ones++;
+ }
+ val = ones & 1;
+#endif
+ return val;
+}
+
+static void build_parity_table(int *parity_table)
+{
+ unsigned int byte;
+ int parity_v;
+ for (byte = 0; byte <= 127; byte++) {
+ parity_v = is_oddparity1p7(byte);
+ parity_table[byte] = parity_v;
+ parity_table[byte | 0x80] = !parity_v;
+ }
+}
+
+static av_cold int init_decoder(AVCodecContext *avctx)
+{
+
+ CCaptionSubContext *ctx = avctx->priv_data;
+
+ build_parity_table(ctx->parity_table);
+ ctx->row_cnt = 0;
+ ctx->buf_len = 256;
+ ctx->buffer = av_realloc(NULL, ctx->buf_len);
+ ctx->index = 0;
+ ctx->edm = 0;
+ /* taking by default roll up to 2 */
+ ctx->rollup = 2;
+ ctx->data_len = 0;
+ memset(ctx->prev_cmd,0,2);
+ ff_ass_subtitle_header_default(avctx);
+ return 0;
+}
+
+static av_cold int close_decoder(AVCodecContext *avctx)
+{
+ CCaptionSubContext *ctx = avctx->priv_data;
+ av_free(ctx->buffer);
+ return 0;
+}
+
+/**
+ * This function after validating parity bit, also remove it from data pair.
+ */
+static int validate_cc_data_pair (unsigned char *cc_data_pair, int *parity_table)
+{
+ unsigned char cc_valid = (*cc_data_pair & 4) >>2;
+ unsigned char cc_type = *cc_data_pair & 3;
+
+ if (!cc_valid)
+ return -1;
+
+ // if EIA-608 data then verify parity.
+ if (cc_type==0 || cc_type==1) {
+ if (!parity_table[cc_data_pair[2]]) {
+ // If the second byte doesn't pass parity, ignore pair
+ return -1;
+ }
+ if (!parity_table[cc_data_pair[1]]) {
+ // The first byte doesn't pass parity, we replace it with a solid blank
+ // and process the pair.
+ cc_data_pair[1]=0x7F;
+ }
+ }
+
+ //Skip non-data
+ if( (cc_data_pair[0] == 0xFA || cc_data_pair[0] == 0xFC || cc_data_pair[0] == 0xFD )
+ && (cc_data_pair[1] & 0x7F) == 0 && (cc_data_pair[2] & 0x7F) == 0)
+ return -1;
+
+ //skip 708 data
+ if(cc_type == 3 || cc_type == 2 )
+ return -1;
+
+ /* remove parity bit */
+ cc_data_pair[1] &= 0x7F;
+ cc_data_pair[2] &= 0x7F;
+
+
+ return 0;
+
+}
+
+/**
+ * @param pts it is required to set end time
+ */
+static void av_always_inline handle_edm(CCaptionSubContext *ctx,int64_t pts)
+{
+ ctx->edm = 1;
+ ctx->data_len = ctx->index;
+ ctx->index = 0;
+ ctx->end_time = pts;
+}
+static int process_cc608(CCaptionSubContext *ctx, int64_t pts, unsigned char hi, unsigned char lo)
+{
+
+ if ( hi == ctx->prev_cmd[0] && lo == ctx->prev_cmd[1]) {
+ /* ignore redundant command */
+ } else if ((hi == 0x14 || hi == 0x15 || hi == 0x1C) && lo == 0x2C) {
+ /* erase display memory */
+ ctx->buffer[ctx->index] = 0;
+ handle_edm(ctx, pts);
+ } else if ( (hi == 0x14 || hi == 0x15 || hi == 0x1C) && lo == 0x25 ) {
+ ctx->rollup = 2;
+ } else if ( (hi == 0x14 || hi == 0x15 || hi == 0x1C) && lo == 0x26 ) {
+ ctx->rollup = 3;
+ } else if ( (hi == 0x14 || hi == 0x15 || hi == 0x1C) && lo == 0x27 ) {
+ ctx->rollup = 4;
+ } else if ( (hi == 0x14 || hi == 0x15 || hi == 0x1C) && lo == 0x2D ) {
+ /* carriage return */
+ if(ctx->buf_len < ctx->index + 3 ) {
+ ctx->buf_len *= 2;
+ ctx->buffer = av_realloc(ctx->buffer, ctx->buf_len);
+ }
+ ctx->row_cnt++;
+ if(ctx->row_cnt == ctx->rollup) {
+ ctx->row_cnt = 0;
+ ctx->buffer[ctx->index ] = 0;
+ handle_edm(ctx, pts);
+ }
+ /* If there is no data or end of data then no point using cr */
+ if(ctx->index) {
+ ctx->buffer[ctx->index] = '\\';
+ ctx->index++;
+ ctx->buffer[ctx->index] = 'N';
+ ctx->index++;
+ }
+ } else if (hi>=0x20) {
+ /* Standard characters (always in pairs) */
+ if(ctx->buf_len < ctx->index + 3 ) {
+ ctx->buf_len *= 2;
+ ctx->buffer = av_realloc(ctx->buffer, ctx->buf_len);
+ }
+ if(!ctx->index)
+ ctx->start_time = pts;
+
+ ctx->buffer[ctx->index] = hi;
+ ctx->index++;
+ if(lo) {
+ ctx->buffer[ctx->index] = lo;
+ ctx->index++;
+ }
+ /* reset prev command since character can repeat */
+ ctx->prev_cmd[0] = 0;
+ ctx->prev_cmd[1] = 0;
+ } else {
+ /* Ignoring all other non data code */
+ }
+
+ /* set prev command */
+ ctx->prev_cmd[0] = hi;
+ ctx->prev_cmd[1] = lo;
+
+ return 0;
+
+}
+static int decode(AVCodecContext *avctx,
+ void *data, int *got_sub,
+ AVPacket *avpkt) {
+ CCaptionSubContext *ctx = avctx->priv_data;
+ AVSubtitle *sub = data;
+ unsigned char *bptr = avpkt->data;
+ int len = avpkt->size;
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < len; i += 3) {
+ unsigned char cc_type = *(bptr + i) & 3;
+ if (validate_cc_data_pair( bptr + i, ctx->parity_table ) )
+ continue;
+ /* ignoring data field 1 */
+ if(cc_type == 1)
+ continue;
+ else
+ process_cc608(ctx, avpkt->pts, *(bptr + i + 1), *(bptr + i + 2));
+ }
+ if(ctx->edm)
+ {
+ int start_time = av_rescale_q(ctx->start_time, avctx->time_base, (AVRational){ 1, 100 });
+ int end_time = av_rescale_q(ctx->end_time, avctx->time_base, (AVRational){ 1, 100 });
+ ret = ff_ass_add_rect(sub, ctx->buffer, start_time, end_time - start_time , 0);
+ if (ret < 0)
+ return ret;
+ sub->pts = av_rescale_q(ctx->start_time, avctx->time_base, AV_TIME_BASE_Q);
+ ctx->edm = 0;
+ }
+
+ *got_sub = sub->num_rects > 0;
+ return 0;
+}
+
+AVCodec ff_ccaption_decoder = {
+ .name = "cc_dec",
+ .long_name = NULL_IF_CONFIG_SMALL("Closed Caption Decoder"),
+ .type = AVMEDIA_TYPE_SUBTITLE,
+ .id = AV_CODEC_ID_EIA_608,
+ .priv_data_size = sizeof(CCaptionSubContext),
+ .init = init_decoder,
+ .close = close_decoder,
+ .decode = decode,
+};
--
1.8.1.4
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