avformat/hlsenc: closed caption tags in the master playlist

doc/muxers.texi

@@ -901,6 +901,43 @@ and they are mapped to the two video only variant streams with audio group names
 
 By default, a single hls variant containing all the encoded streams is created.
 
+@item cc_stream_map
+Map string which specifies different closed captions groups and their
+attributes. The closed captions stream groups are separated by space.
+Expected string format is like this
+"ccgroup:<group name>,instreamid:<INSTREAM-ID>,language:<language code> ....".
+'ccgroup' and 'instreamid' are mandatory attributes. 'language' is an optional
+attribute.
+The closed captions groups configured using this option are mapped to different
+variant streams by providing the same 'ccgroup' name in the
+@code{var_stream_map} string. If @code{var_stream_map} is not set, then the
+first available ccgroup in @code{cc_stream_map} is mapped to the output variant
+stream. The examples for these two use cases are given below.
+
+@example
+ffmpeg -re -i in.ts -b:v 1000k -b:a 64k -a53cc 1 -f hls \
+  -cc_stream_map "ccgroup:cc,instreamid:CC1,language:en" \
+  -master_pl_name master.m3u8 \
+  http://example.com/live/out.m3u8
+@end example
+This example adds @code{#EXT-X-MEDIA} tag with @code{TYPE=CLOSED-CAPTIONS} in
+the master playlist with group name 'cc', langauge 'en' (english) and
+INSTREAM-ID 'CC1'. Also, it adds @code{CLOSED-CAPTIONS} attribute with group
+name 'cc' for the output variant stream.
+@example
+ffmpeg -re -i in.ts -b:v:0 1000k -b:v:1 256k -b:a:0 64k -b:a:1 32k \
+  -a53cc:0 1 -a53cc:1 1\
+  -map 0:v -map 0:a -map 0:v -map 0:a -f hls \
+  -cc_stream_map "ccgroup:cc,instreamid:CC1,language:en ccgroup:cc,instreamid:CC2,language:sp" \
+  -var_stream_map "v:0,a:0,ccgroup:cc v:1,a:1,ccgroup:cc" \
+  -master_pl_name master.m3u8 \
+  http://example.com/live/out_%v.m3u8
+@end example
+This example adds two @code{#EXT-X-MEDIA} tags with @code{TYPE=CLOSED-CAPTIONS} in
+the master playlist for the INSTREAM-IDs 'CC1' and 'CC2'. Also, it adds
+@code{CLOSED-CAPTIONS} attribute with group name 'cc' for the two output variant
+streams.
+
 @item master_pl_name
 Create HLS master playlist with the given name.
 

libavformat/dashenc.c

@@ -820,7 +820,7 @@ static int write_manifest(AVFormatContext *s, int final)
                 stream_bitrate += max_audio_bitrate;
             }
             get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
-            ff_hls_write_stream_info(st, out, stream_bitrate, playlist_file, agroup, NULL);
+            ff_hls_write_stream_info(st, out, stream_bitrate, playlist_file, agroup, NULL, NULL);
         }
         avio_close(out);
         if (use_rename)

libavformat/hlsenc.c

@@ -152,9 +152,16 @@ typedef struct VariantStream {
     unsigned int nb_streams;
     int m3u8_created; /* status of media play-list creation */
     char *agroup; /* audio group name */
+    char *ccgroup; /* closed caption group name */
     char *baseurl;
 } VariantStream;
 
+typedef struct ClosedCaptionsStream {
+    char *ccgroup; /* closed caption group name */
+    char *instreamid; /* closed captions INSTREAM-ID */
+    char *language; /* closed captions langauge */
+} ClosedCaptionsStream;
+
 typedef struct HLSContext {
     const AVClass *class;  // Class for private options.
     int64_t start_sequence;
@@ -203,11 +210,14 @@ typedef struct HLSContext {
 
     VariantStream *var_streams;
     unsigned int nb_varstreams;
+    ClosedCaptionsStream *cc_streams;
+    unsigned int nb_ccstreams;
 
     int master_m3u8_created; /* status of master play-list creation */
     char *master_m3u8_url; /* URL of the master m3u8 file */
     int version; /* HLS version */
     char *var_stream_map; /* user specified variant stream map string */
+    char *cc_stream_map; /* user specified closed caption streams map string */
     char *master_pl_name;
     unsigned int master_publish_rate;
     int http_persistent;
@@ -1167,7 +1177,8 @@ static int create_master_playlist(AVFormatContext *s,
     AVDictionary *options = NULL;
     unsigned int i, j;
     int m3u8_name_size, ret, bandwidth;
-    char *m3u8_rel_name;
+    char *m3u8_rel_name, *ccgroup;
+    ClosedCaptionsStream *ccs;
 
     input_vs->m3u8_created = 1;
     if (!hls->master_m3u8_created) {
@@ -1194,6 +1205,16 @@ static int create_master_playlist(AVFormatContext *s,
 
     ff_hls_write_playlist_version(hls->m3u8_out, hls->version);
 
+    for (i = 0; i < hls->nb_ccstreams; i++) {
+        ccs = &(hls->cc_streams[i]);
+        avio_printf(hls->m3u8_out, "#EXT-X-MEDIA:TYPE=CLOSED-CAPTIONS");
+        avio_printf(hls->m3u8_out, ",GROUP-ID=\"%s\"", ccs->ccgroup);
+        avio_printf(hls->m3u8_out, ",NAME=\"%s\"", ccs->instreamid);
+        if (ccs->language)
+            avio_printf(hls->m3u8_out, ",LANGUAGE=\"%s\"", ccs->language);
+        avio_printf(hls->m3u8_out, ",INSTREAM-ID=\"%s\"\n", ccs->instreamid);
+    }
+
     /* For audio only variant streams add #EXT-X-MEDIA tag with attributes*/
     for (i = 0; i < hls->nb_varstreams; i++) {
         vs = &(hls->var_streams[i]);
@@ -1278,8 +1299,23 @@ static int create_master_playlist(AVFormatContext *s,
             bandwidth += aud_st->codecpar->bit_rate;
         bandwidth += bandwidth / 10;
 
+        ccgroup = NULL;
+        if (vid_st && vs->ccgroup) {
+            /* check if this group name is available in the cc map string */
+            for (j = 0; j < hls->nb_ccstreams; j++) {
+                ccs = &(hls->cc_streams[j]);
+                if (!av_strcasecmp(ccs->ccgroup, vs->ccgroup)) {
+                    ccgroup = vs->ccgroup;
+                    break;
+                }
+            }
+            if (j == hls->nb_ccstreams)
+                av_log(NULL, AV_LOG_WARNING, "mapping ccgroup %s not found\n",
+                        vs->ccgroup);
+        }
+
         ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
-                aud_st ? vs->agroup : NULL, vs->codec_attr);
+                aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup);
 
         av_freep(&m3u8_rel_name);
     }
@@ -1766,6 +1802,11 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
                 if (!vs->agroup)
                     return AVERROR(ENOMEM);
                 continue;
+            } else if (av_strstart(keyval, "ccgroup:", &val)) {
+                vs->ccgroup = av_strdup(val);
+                if (!vs->ccgroup)
+                    return AVERROR(ENOMEM);
+                continue;
             } else if (av_strstart(keyval, "v:", &val)) {
                 codec_type = AVMEDIA_TYPE_VIDEO;
             } else if (av_strstart(keyval, "a:", &val)) {
@@ -1796,9 +1837,94 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
     return 0;
 }
 
+static int parse_cc_stream_mapstring(AVFormatContext *s)
+{
+    HLSContext *hls = s->priv_data;
+    int nb_ccstreams;
+    char *p, *q, *saveptr1, *saveptr2, *ccstr, *keyval;
+    const char *val;
+    ClosedCaptionsStream *ccs;
+
+    p = av_strdup(hls->cc_stream_map);
+    q = p;
+    while(av_strtok(q, " \t", &saveptr1)) {
+        q = NULL;
+        hls->nb_ccstreams++;
+    }
+    av_freep(&p);
+
+    hls->cc_streams = av_mallocz(sizeof(*hls->cc_streams) * hls->nb_ccstreams);
+    if (!hls->cc_streams)
+        return AVERROR(ENOMEM);
+
+    p = hls->cc_stream_map;
+    nb_ccstreams = 0;
+    while (ccstr = av_strtok(p, " \t", &saveptr1)) {
+        p = NULL;
+
+        if (nb_ccstreams < hls->nb_ccstreams)
+            ccs = &(hls->cc_streams[nb_ccstreams++]);
+        else
+            return AVERROR(EINVAL);
+
+        while (keyval = av_strtok(ccstr, ",", &saveptr2)) {
+            ccstr = NULL;
+
+            if (av_strstart(keyval, "ccgroup:", &val)) {
+                ccs->ccgroup = av_strdup(val);
+                if (!ccs->ccgroup)
+                    return AVERROR(ENOMEM);
+            } else if (av_strstart(keyval, "instreamid:", &val)) {
+                ccs->instreamid = av_strdup(val);
+                if (!ccs->instreamid)
+                    return AVERROR(ENOMEM);
+            } else if (av_strstart(keyval, "language:", &val)) {
+                ccs->language = av_strdup(val);
+                if (!ccs->language)
+                    return AVERROR(ENOMEM);
+            } else {
+                av_log(s, AV_LOG_ERROR, "Invalid keyval %s\n", keyval);
+                return AVERROR(EINVAL);
+            }
+        }
+
+        if (!ccs->ccgroup || !ccs->instreamid) {
+            av_log(s, AV_LOG_ERROR, "Insufficient parameters in cc stream map string\n");
+            return AVERROR(EINVAL);
+        }
+
+        if (av_strstart(ccs->instreamid, "CC", &val)) {
+            if(atoi(val) < 1 || atoi(val) > 4) {
+                av_log(s, AV_LOG_ERROR, "Invalid instream ID CC index %d in %s, range 1-4\n",
+                       atoi(val), ccs->instreamid);
+                return AVERROR(EINVAL);
+            }
+        } else if (av_strstart(ccs->instreamid, "SERVICE", &val)) {
+            if(atoi(val) < 1 || atoi(val) > 63) {
+                av_log(s, AV_LOG_ERROR, "Invalid instream ID SERVICE index %d in %s, range 1-63 \n",
+                       atoi(val), ccs->instreamid);
+                return AVERROR(EINVAL);
+            }
+        } else {
+            av_log(s, AV_LOG_ERROR, "Invalid instream ID %s, supported are CCn or SERIVICEn\n",
+                   ccs->instreamid);
+            return AVERROR(EINVAL);
+        }
+    }
+
+    return 0;
+}
+
 static int update_variant_stream_info(AVFormatContext *s) {
     HLSContext *hls = s->priv_data;
     unsigned int i;
+    int ret = 0;
+
+    if (hls->cc_stream_map) {
+        ret = parse_cc_stream_mapstring(s);
+        if (ret < 0)
+            return ret;
+    }
 
     if (hls->var_stream_map) {
         return parse_variant_stream_mapstring(s);
@@ -1816,6 +1942,13 @@ static int update_variant_stream_info(AVFormatContext *s) {
         if (!hls->var_streams[0].streams)
             return AVERROR(ENOMEM);
 
+        //by default, the first available ccgroup is mapped to the variant stream
+        if (hls->nb_ccstreams) {
+            hls->var_streams[0].ccgroup = av_strdup(hls->cc_streams[0].ccgroup);
+            if (!hls->var_streams[0].ccgroup)
+                return AVERROR(ENOMEM);
+        }
+
         for (i = 0; i < s->nb_streams; i++)
             hls->var_streams[0].streams[i] = s->streams[i];
     }
@@ -2192,13 +2325,22 @@ failed:
     av_freep(&vs->m3u8_name);
     av_freep(&vs->streams);
     av_freep(&vs->agroup);
+    av_freep(&vs->ccgroup);
     av_freep(&vs->baseurl);
     }
 
+    for (i = 0; i < hls->nb_ccstreams; i++) {
+        ClosedCaptionsStream *ccs = &hls->cc_streams[i];
+        av_freep(&ccs->ccgroup);
+        av_freep(&ccs->instreamid);
+        av_freep(&ccs->language);
+    }
+
     ff_format_io_close(s, &hls->m3u8_out);
     ff_format_io_close(s, &hls->sub_m3u8_out);
     av_freep(&hls->key_basename);
     av_freep(&hls->var_streams);
+    av_freep(&hls->cc_streams);
     av_freep(&hls->master_m3u8_url);
     return 0;
 }
@@ -2535,13 +2677,21 @@ fail:
             av_freep(&vs->vtt_m3u8_name);
             av_freep(&vs->streams);
             av_freep(&vs->agroup);
+            av_freep(&vs->ccgroup);
             av_freep(&vs->baseurl);
             if (vs->avf)
                 avformat_free_context(vs->avf);
             if (vs->vtt_avf)
                 avformat_free_context(vs->vtt_avf);
         }
+        for (i = 0; i < hls->nb_ccstreams; i++) {
+            ClosedCaptionsStream *ccs = &hls->cc_streams[i];
+            av_freep(&ccs->ccgroup);
+            av_freep(&ccs->instreamid);
+            av_freep(&ccs->language);
+        }
         av_freep(&hls->var_streams);
+        av_freep(&hls->cc_streams);
         av_freep(&hls->master_m3u8_url);
     }
 
@@ -2601,6 +2751,7 @@ static const AVOption options[] = {
     {"datetime", "current datetime as YYYYMMDDhhmmss", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_START_SEQUENCE_AS_FORMATTED_DATETIME }, INT_MIN, INT_MAX, E, "start_sequence_source_type" },
     {"http_user_agent", "override User-Agent field in HTTP header", OFFSET(user_agent), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},
     {"var_stream_map", "Variant stream map string", OFFSET(var_stream_map), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},
+    {"cc_stream_map", "Closed captions stream map string", OFFSET(cc_stream_map), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},
     {"master_pl_name", "Create HLS master playlist with this name", OFFSET(master_pl_name), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},
     {"master_pl_publish_rate", "Publish master play list every after this many segment intervals", OFFSET(master_publish_rate), AV_OPT_TYPE_INT, {.i64 = 0}, 0, UINT_MAX, E},
     {"http_persistent", "Use persistent HTTP connections", OFFSET(http_persistent), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },

libavformat/hlsplaylist.c

@@ -47,7 +47,8 @@ void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
 
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
                               int bandwidth, char *filename, char *agroup,
-                              char *codecs) {
+                              char *codecs, char *ccgroup) {
+
     if (!out || !filename)
         return;
 
@@ -65,6 +66,8 @@ void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
         avio_printf(out, ",CODECS=\"%s\"", codecs);
     if (agroup && strlen(agroup) > 0)
         avio_printf(out, ",AUDIO=\"group_%s\"", agroup);
+    if (ccgroup && strlen(ccgroup) > 0)
+        avio_printf(out, ",CLOSED-CAPTIONS=\"%s\"", ccgroup);
     avio_printf(out, "\n%s\n\n", filename);
 }
 

libavformat/hlsplaylist.h

@@ -41,7 +41,7 @@ void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
                                   char *filename, int name_id, int is_default);
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
                               int bandwidth, char *filename, char *agroup,
-                              char *codecs);
+                              char *codecs, char *ccgroup);
 void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,
                                   int target_duration, int64_t sequence,
                                   uint32_t playlist_type);