lavf: replace AVStream.codec with AVStream.codecpar

Currently, AVStream contains an embedded AVCodecContext instance, which
is used by demuxers to export stream parameters to the caller and by
muxers to receive stream parameters from the caller. It is also used
internally as the codec context that is passed to parsers.

In addition, it is also widely used by the callers as the decoding (when
demuxer) or encoding (when muxing) context, though this has been
officially discouraged since Libav 11.

There are multiple important problems with this approach:
    - the fields in AVCodecContext are in general one of
        * stream parameters
        * codec options
        * codec state
      However, it's not clear which ones are which. It is consequently
      unclear which fields are a demuxer allowed to set or a muxer allowed to
      read. This leads to erratic behaviour depending on whether decoding or
      encoding is being performed or not (and whether it uses the AVStream
      embedded codec context).
    - various synchronization issues arising from the fact that the same
      context is used by several different APIs (muxers/demuxers,
      parsers, bitstream filters and encoders/decoders) simultaneously, with
      there being no clear rules for who can modify what and the different
      processes being typically delayed with respect to each other.
    - avformat_find_stream_info() making it necessary to support opening
      and closing a single codec context multiple times, thus
      complicating the semantics of freeing various allocated objects in the
      codec context.

Those problems are resolved by replacing the AVStream embedded codec
context with a newly added AVCodecParameters instance, which stores only
the stream parameters exported by the demuxers or read by the muxers.

1 files changed, 29 insertions, 29 deletions

diff --git a/libavformat/avisynth.c b/libavformat/avisynth.c
index 1a6a73f53e..b00f9bc42e 100644
--- a/libavformat/avisynth.c
+++ b/libavformat/avisynth.c
@@ -233,10 +233,10 @@ static int avisynth_create_stream_video(AVFormatContext *s, AVStream *st)
     AviSynthContext *avs = s->priv_data;
     int planar = 0; // 0: packed, 1: YUV, 2: Y8
 
-    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
-    st->codec->codec_id   = AV_CODEC_ID_RAWVIDEO;
-    st->codec->width      = avs->vi->width;
-    st->codec->height     = avs->vi->height;
+    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
+    st->codecpar->codec_id   = AV_CODEC_ID_RAWVIDEO;
+    st->codecpar->width      = avs->vi->width;
+    st->codecpar->height     = avs->vi->height;
 
     st->time_base         = (AVRational) { avs->vi->fps_denominator,
                                            avs->vi->fps_numerator };
@@ -249,38 +249,38 @@ static int avisynth_create_stream_video(AVFormatContext *s, AVStream *st)
     switch (avs->vi->pixel_type) {
 #ifdef USING_AVISYNTH
     case AVS_CS_YV24:
-        st->codec->pix_fmt = AV_PIX_FMT_YUV444P;
-        planar             = 1;
+        st->codecpar->format = AV_PIX_FMT_YUV444P;
+        planar               = 1;
         break;
     case AVS_CS_YV16:
-        st->codec->pix_fmt = AV_PIX_FMT_YUV422P;
-        planar             = 1;
+        st->codecpar->format = AV_PIX_FMT_YUV422P;
+        planar               = 1;
         break;
     case AVS_CS_YV411:
-        st->codec->pix_fmt = AV_PIX_FMT_YUV411P;
-        planar             = 1;
+        st->codecpar->format = AV_PIX_FMT_YUV411P;
+        planar               = 1;
         break;
     case AVS_CS_Y8:
-        st->codec->pix_fmt = AV_PIX_FMT_GRAY8;
-        planar             = 2;
+        st->codecpar->format = AV_PIX_FMT_GRAY8;
+        planar               = 2;
         break;
 #endif
     case AVS_CS_BGR24:
-        st->codec->pix_fmt = AV_PIX_FMT_BGR24;
+        st->codecpar->format = AV_PIX_FMT_BGR24;
         break;
     case AVS_CS_BGR32:
-        st->codec->pix_fmt = AV_PIX_FMT_RGB32;
+        st->codecpar->format = AV_PIX_FMT_RGB32;
         break;
     case AVS_CS_YUY2:
-        st->codec->pix_fmt = AV_PIX_FMT_YUYV422;
+        st->codecpar->format = AV_PIX_FMT_YUYV422;
         break;
     case AVS_CS_YV12:
-        st->codec->pix_fmt = AV_PIX_FMT_YUV420P;
-        planar             = 1;
+        st->codecpar->format = AV_PIX_FMT_YUV420P;
+        planar               = 1;
         break;
     case AVS_CS_I420: // Is this even used anywhere?
-        st->codec->pix_fmt = AV_PIX_FMT_YUV420P;
-        planar             = 1;
+        st->codecpar->format = AV_PIX_FMT_YUV420P;
+        planar               = 1;
         break;
     default:
         av_log(s, AV_LOG_ERROR,
@@ -309,28 +309,28 @@ static int avisynth_create_stream_audio(AVFormatContext *s, AVStream *st)
 {
     AviSynthContext *avs = s->priv_data;
 
-    st->codec->codec_type  = AVMEDIA_TYPE_AUDIO;
-    st->codec->sample_rate = avs->vi->audio_samples_per_second;
-    st->codec->channels    = avs->vi->nchannels;
+    st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
+    st->codecpar->sample_rate = avs->vi->audio_samples_per_second;
+    st->codecpar->channels    = avs->vi->nchannels;
     st->time_base          = (AVRational) { 1,
                                             avs->vi->audio_samples_per_second };
     st->duration           = avs->vi->num_audio_samples;
 
     switch (avs->vi->sample_type) {
     case AVS_SAMPLE_INT8:
-        st->codec->codec_id = AV_CODEC_ID_PCM_U8;
+        st->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
         break;
     case AVS_SAMPLE_INT16:
-        st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;
+        st->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
         break;
     case AVS_SAMPLE_INT24:
-        st->codec->codec_id = AV_CODEC_ID_PCM_S24LE;
+        st->codecpar->codec_id = AV_CODEC_ID_PCM_S24LE;
         break;
     case AVS_SAMPLE_INT32:
-        st->codec->codec_id = AV_CODEC_ID_PCM_S32LE;
+        st->codecpar->codec_id = AV_CODEC_ID_PCM_S32LE;
         break;
     case AVS_SAMPLE_FLOAT:
-        st->codec->codec_id = AV_CODEC_ID_PCM_F32LE;
+        st->codecpar->codec_id = AV_CODEC_ID_PCM_F32LE;
         break;
     default:
         av_log(s, AV_LOG_ERROR,
@@ -639,7 +639,7 @@ static int avisynth_read_packet(AVFormatContext *s, AVPacket *pkt)
     /* If either stream reaches EOF, try to read the other one before
      * giving up. */
     avisynth_next_stream(s, &st, pkt, &discard);
-    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
+    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
         ret = avisynth_read_packet_video(s, pkt, discard);
         if (ret == AVERROR_EOF && avs_has_audio(avs->vi)) {
             avisynth_next_stream(s, &st, pkt, &discard);
@@ -681,7 +681,7 @@ static int avisynth_read_seek(AVFormatContext *s, int stream_index,
     samplerate = (AVRational) { avs->vi->audio_samples_per_second, 1 };
 
     st = s->streams[stream_index];
-    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
+    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
         /* AviSynth frame counts are signed int. */
         if ((timestamp >= avs->vi->num_frames) ||
             (timestamp > INT_MAX)              ||