applehttp: Expose the stream bitrate via metadata

This helps callers to intelligently switch between bitrate
variants.
Signed-off-by: Martin Storsjö <martin@martin.st>

doc/demuxers.texi

@@ -72,5 +72,7 @@ This demuxer presents all AVStreams from all variant streams.
 The id field is set to the bitrate variant index number. By setting
 the discard flags on AVStreams (by pressing 'a' or 'v' in ffplay),
 the caller can decide which variant streams to actually receive.
+The total bitrate of the variant that the stream belongs to is
+available in a metadata key named "variant_bitrate".
 
 @c man end INPUT DEVICES

libavformat/applehttp.c

@@ -367,6 +367,7 @@ static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
     for (i = 0; i < c->n_variants; i++) {
         struct variant *v = c->variants[i];
         AVInputFormat *in_fmt = NULL;
+        char bitrate_str[20];
         if (v->n_segments == 0)
             continue;
 
@@ -393,6 +394,7 @@ static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
         if (ret < 0)
             goto fail;
         v->stream_offset = stream_offset;
+        snprintf(bitrate_str, sizeof(bitrate_str), "%d", v->bandwidth);
         /* Create new AVStreams for each stream in this variant */
         for (j = 0; j < v->ctx->nb_streams; j++) {
             AVStream *st = av_new_stream(s, i);
@@ -401,6 +403,7 @@ static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
                 goto fail;
             }
             avcodec_copy_context(st->codec, v->ctx->streams[j]->codec);
+            av_metadata_set2(&st->metadata, "variant_bitrate", bitrate_str, 0);
         }
         stream_offset += v->ctx->nb_streams;
     }

libavformat/avformat.h

@@ -104,6 +104,7 @@ struct AVFormatContext;
  * service_provider -- name of the service provider in broadcasting.
  * title        -- name of the work.
  * track        -- number of this work in the set, can be in form current/total.
+ * variant_bitrate -- the total bitrate of the bitrate variant that the current stream is part of
  */
 
 #define AV_METADATA_MATCH_CASE      1

libavformat/version.h

@@ -25,7 +25,7 @@
 
 #define LIBAVFORMAT_VERSION_MAJOR 53
 #define LIBAVFORMAT_VERSION_MINOR  0
-#define LIBAVFORMAT_VERSION_MICRO  0
+#define LIBAVFORMAT_VERSION_MICRO  1
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \