avformat/utils: Move av_find_best_stream to avformat.c

It is not forbidden to call this with a muxer, so it is moved to
avformat.c and not demux_utils.c. ff_find_decoder(), which is used
by av_find_best_stream() is also moved as well, despite being even
more geared towards demuxers.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/libavformat/avformat.c b/libavformat/avformat.c
index 2b012a903f..a828e6db55 100644
--- a/libavformat/avformat.c
+++ b/libavformat/avformat.c
@@ -312,6 +312,72 @@ int av_find_default_stream_index(AVFormatContext *s)
     return best_stream;
 }
 
+int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type,
+                        int wanted_stream_nb, int related_stream,
+                        const AVCodec **decoder_ret, int flags)
+{
+    int nb_streams = ic->nb_streams;
+    int ret = AVERROR_STREAM_NOT_FOUND;
+    int best_count = -1, best_multiframe = -1, best_disposition = -1;
+    int count, multiframe, disposition;
+    int64_t best_bitrate = -1;
+    int64_t bitrate;
+    unsigned *program = NULL;
+    const AVCodec *decoder = NULL, *best_decoder = NULL;
+
+    if (related_stream >= 0 && wanted_stream_nb < 0) {
+        AVProgram *p = av_find_program_from_stream(ic, NULL, related_stream);
+        if (p) {
+            program    = p->stream_index;
+            nb_streams = p->nb_stream_indexes;
+        }
+    }
+    for (unsigned i = 0; i < nb_streams; i++) {
+        int real_stream_index = program ? program[i] : i;
+        AVStream *st          = ic->streams[real_stream_index];
+        AVCodecParameters *par = st->codecpar;
+        if (par->codec_type != type)
+            continue;
+        if (wanted_stream_nb >= 0 && real_stream_index != wanted_stream_nb)
+            continue;
+        if (type == AVMEDIA_TYPE_AUDIO && !(par->ch_layout.nb_channels && par->sample_rate))
+            continue;
+        if (decoder_ret) {
+            decoder = ff_find_decoder(ic, st, par->codec_id);
+            if (!decoder) {
+                if (ret < 0)
+                    ret = AVERROR_DECODER_NOT_FOUND;
+                continue;
+            }
+        }
+        disposition = !(st->disposition & (AV_DISPOSITION_HEARING_IMPAIRED | AV_DISPOSITION_VISUAL_IMPAIRED))
+                      + !! (st->disposition & AV_DISPOSITION_DEFAULT);
+        count = ffstream(st)->codec_info_nb_frames;
+        bitrate = par->bit_rate;
+        multiframe = FFMIN(5, count);
+        if ((best_disposition >  disposition) ||
+            (best_disposition == disposition && best_multiframe >  multiframe) ||
+            (best_disposition == disposition && best_multiframe == multiframe && best_bitrate >  bitrate) ||
+            (best_disposition == disposition && best_multiframe == multiframe && best_bitrate == bitrate && best_count >= count))
+            continue;
+        best_disposition = disposition;
+        best_count   = count;
+        best_bitrate = bitrate;
+        best_multiframe = multiframe;
+        ret          = real_stream_index;
+        best_decoder = decoder;
+        if (program && i == nb_streams - 1 && ret < 0) {
+            program    = NULL;
+            nb_streams = ic->nb_streams;
+            /* no related stream found, try again with everything */
+            i = 0;
+        }
+    }
+    if (decoder_ret)
+        *decoder_ret = best_decoder;
+    return ret;
+}
+
 /**
  * Matches a stream specifier (but ignores requested index).
  *
@@ -595,3 +661,21 @@ AVRational av_stream_get_codec_timebase(const AVStream *st)
     // See avformat_transfer_internal_stream_timing_info() TODO.
     return cffstream(st)->avctx->time_base;
 }
+
+const AVCodec *ff_find_decoder(AVFormatContext *s, const AVStream *st,
+                               enum AVCodecID codec_id)
+{
+    switch (st->codecpar->codec_type) {
+    case AVMEDIA_TYPE_VIDEO:
+        if (s->video_codec)    return s->video_codec;
+        break;
+    case AVMEDIA_TYPE_AUDIO:
+        if (s->audio_codec)    return s->audio_codec;
+        break;
+    case AVMEDIA_TYPE_SUBTITLE:
+        if (s->subtitle_codec) return s->subtitle_codec;
+        break;
+    }
+
+    return avcodec_find_decoder(codec_id);
+}