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/asfenc.c b/libavformat/asfenc.c
index f6608d5292..79eb08310b 100644
--- a/libavformat/asfenc.c
+++ b/libavformat/asfenc.c
@@ -377,7 +377,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
     int header_size, n, extra_size, extra_size2, wav_extra_size, file_time;
     int has_title;
     int metadata_count;
-    AVCodecContext *enc;
+    AVCodecParameters *par;
     int64_t header_offset, cur_pos, hpos;
     int bit_rate;
     int64_t duration;
@@ -396,11 +396,11 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
 
     bit_rate = 0;
     for (n = 0; n < s->nb_streams; n++) {
-        enc = s->streams[n]->codec;
+        par = s->streams[n]->codecpar;
 
         avpriv_set_pts_info(s->streams[n], 32, 1, 1000); /* 32 bit pts in ms */
 
-        bit_rate += enc->bit_rate;
+        bit_rate += par->bit_rate;
     }
 
     if (asf->is_streamed) {
@@ -479,11 +479,11 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
         int64_t es_pos;
         //        ASFStream *stream = &asf->streams[n];
 
-        enc                 = s->streams[n]->codec;
+        par                 = s->streams[n]->codecpar;
         asf->streams[n].num = n + 1;
         asf->streams[n].seq = 0;
 
-        switch (enc->codec_type) {
+        switch (par->codec_type) {
         case AVMEDIA_TYPE_AUDIO:
             wav_extra_size = 0;
             extra_size     = 18 + wav_extra_size;
@@ -491,14 +491,14 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
             break;
         default:
         case AVMEDIA_TYPE_VIDEO:
-            wav_extra_size = enc->extradata_size;
+            wav_extra_size = par->extradata_size;
             extra_size     = 0x33 + wav_extra_size;
             extra_size2    = 0;
             break;
         }
 
         hpos = put_header(pb, &ff_asf_stream_header);
-        if (enc->codec_type == AVMEDIA_TYPE_AUDIO) {
+        if (par->codec_type == AVMEDIA_TYPE_AUDIO) {
             put_guid(pb, &ff_asf_audio_stream);
             put_guid(pb, &ff_asf_audio_conceal_spread);
         } else {
@@ -512,9 +512,9 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
         avio_wl16(pb, n + 1); /* stream number */
         avio_wl32(pb, 0); /* ??? */
 
-        if (enc->codec_type == AVMEDIA_TYPE_AUDIO) {
+        if (par->codec_type == AVMEDIA_TYPE_AUDIO) {
             /* WAVEFORMATEX header */
-            int wavsize = ff_put_wav_header(pb, enc);
+            int wavsize = ff_put_wav_header(s, pb, par);
 
             if (wavsize < 0)
                 return -1;
@@ -526,23 +526,23 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
             }
             /* ERROR Correction */
             avio_w8(pb, 0x01);
-            if (enc->codec_id == AV_CODEC_ID_ADPCM_G726 || !enc->block_align) {
+            if (par->codec_id == AV_CODEC_ID_ADPCM_G726 || !par->block_align) {
                 avio_wl16(pb, 0x0190);
                 avio_wl16(pb, 0x0190);
             } else {
-                avio_wl16(pb, enc->block_align);
-                avio_wl16(pb, enc->block_align);
+                avio_wl16(pb, par->block_align);
+                avio_wl16(pb, par->block_align);
             }
             avio_wl16(pb, 0x01);
             avio_w8(pb, 0x00);
         } else {
-            avio_wl32(pb, enc->width);
-            avio_wl32(pb, enc->height);
+            avio_wl32(pb, par->width);
+            avio_wl32(pb, par->height);
             avio_w8(pb, 2); /* ??? */
-            avio_wl16(pb, 40 + enc->extradata_size); /* size */
+            avio_wl16(pb, 40 + par->extradata_size); /* size */
 
             /* BITMAPINFOHEADER header */
-            ff_put_bmp_header(pb, enc, ff_codec_bmp_tags, 1);
+            ff_put_bmp_header(pb, par, ff_codec_bmp_tags, 1);
         }
         end_header(pb, hpos);
     }
@@ -556,17 +556,17 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
         const AVCodecDescriptor *codec_desc;
         const char *desc;
 
-        enc  = s->streams[n]->codec;
-        codec_desc = avcodec_descriptor_get(enc->codec_id);
+        par  = s->streams[n]->codecpar;
+        codec_desc = avcodec_descriptor_get(par->codec_id);
 
-        if (enc->codec_type == AVMEDIA_TYPE_AUDIO)
+        if (par->codec_type == AVMEDIA_TYPE_AUDIO)
             avio_wl16(pb, 2);
-        else if (enc->codec_type == AVMEDIA_TYPE_VIDEO)
+        else if (par->codec_type == AVMEDIA_TYPE_VIDEO)
             avio_wl16(pb, 1);
         else
             avio_wl16(pb, -1);
 
-        if (enc->codec_id == AV_CODEC_ID_WMAV2)
+        if (par->codec_id == AV_CODEC_ID_WMAV2)
             desc = "Windows Media Audio V8";
         else
             desc = codec_desc ? codec_desc->name : NULL;
@@ -591,14 +591,14 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size,
         avio_wl16(pb, 0); /* no parameters */
 
         /* id */
-        if (enc->codec_type == AVMEDIA_TYPE_AUDIO) {
+        if (par->codec_type == AVMEDIA_TYPE_AUDIO) {
             avio_wl16(pb, 2);
-            avio_wl16(pb, enc->codec_tag);
+            avio_wl16(pb, par->codec_tag);
         } else {
             avio_wl16(pb, 4);
-            avio_wl32(pb, enc->codec_tag);
+            avio_wl32(pb, par->codec_tag);
         }
-        if (!enc->codec_tag)
+        if (!par->codec_tag)
             return -1;
     }
     end_header(pb, hpos);
@@ -813,7 +813,7 @@ static void put_frame(AVFormatContext *s, ASFStream *stream, AVStream *avst,
                         PACKET_HEADER_MIN_SIZE - 1;
 
             if (frag_len1 < payload_len &&
-                avst->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
+                avst->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
                 flush_packet(s);
                 continue;
             }
@@ -855,16 +855,16 @@ static int asf_write_packet(AVFormatContext *s, AVPacket *pkt)
     AVIOContext *pb = s->pb;
     ASFStream *stream;
     int64_t duration;
-    AVCodecContext *codec;
+    AVCodecParameters *par;
     int64_t packet_st, pts;
     int start_sec, i;
     int flags = pkt->flags;
     uint64_t offset = avio_tell(pb);
 
-    codec  = s->streams[pkt->stream_index]->codec;
+    par  = s->streams[pkt->stream_index]->codecpar;
     stream = &asf->streams[pkt->stream_index];
 
-    if (codec->codec_type == AVMEDIA_TYPE_AUDIO)
+    if (par->codec_type == AVMEDIA_TYPE_AUDIO)
         flags &= ~AV_PKT_FLAG_KEY;
 
     pts = (pkt->pts != AV_NOPTS_VALUE) ? pkt->pts : pkt->dts;