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, 40 insertions, 40 deletions

diff --git a/libavformat/oggenc.c b/libavformat/oggenc.c
index 8f8a08f1bd..2fef74ad7a 100644
--- a/libavformat/oggenc.c
+++ b/libavformat/oggenc.c
@@ -212,7 +212,7 @@ static int ogg_buffer_data(AVFormatContext *s, AVStream *st,
     int i, segments, len, flush = 0;
 
     // Handles VFR by flushing page because this frame needs to have a timestamp
-    if (st->codec->codec_id == AV_CODEC_ID_THEORA && !header &&
+    if (st->codecpar->codec_id == AV_CODEC_ID_THEORA && !header &&
         ogg_granule_to_timestamp(oggstream, granule) >
         ogg_granule_to_timestamp(oggstream, oggstream->last_granule) + 1) {
         if (oggstream->page.granule != -1)
@@ -294,13 +294,13 @@ static uint8_t *ogg_write_vorbiscomment(int offset, int bitexact,
     return p0;
 }
 
-static int ogg_build_flac_headers(AVCodecContext *avctx,
+static int ogg_build_flac_headers(AVCodecParameters *par,
                                   OGGStreamContext *oggstream, int bitexact,
                                   AVDictionary **m)
 {
     uint8_t *p;
 
-    if (avctx->extradata_size < FLAC_STREAMINFO_SIZE)
+    if (par->extradata_size < FLAC_STREAMINFO_SIZE)
         return AVERROR(EINVAL);
 
     // first packet: STREAMINFO
@@ -317,7 +317,7 @@ static int ogg_build_flac_headers(AVCodecContext *avctx,
     bytestream_put_buffer(&p, "fLaC", 4);
     bytestream_put_byte(&p, 0x00); // streaminfo
     bytestream_put_be24(&p, 34);
-    bytestream_put_buffer(&p, avctx->extradata, FLAC_STREAMINFO_SIZE);
+    bytestream_put_buffer(&p, par->extradata, FLAC_STREAMINFO_SIZE);
 
     // second packet: VorbisComment
     p = ogg_write_vorbiscomment(4, bitexact, &oggstream->header_len[1], m, 0);
@@ -332,13 +332,13 @@ static int ogg_build_flac_headers(AVCodecContext *avctx,
 
 #define SPEEX_HEADER_SIZE 80
 
-static int ogg_build_speex_headers(AVCodecContext *avctx,
+static int ogg_build_speex_headers(AVCodecParameters *par,
                                    OGGStreamContext *oggstream, int bitexact,
                                    AVDictionary **m)
 {
     uint8_t *p;
 
-    if (avctx->extradata_size < SPEEX_HEADER_SIZE)
+    if (par->extradata_size < SPEEX_HEADER_SIZE)
         return -1;
 
     // first packet: Speex header
@@ -347,7 +347,7 @@ static int ogg_build_speex_headers(AVCodecContext *avctx,
         return AVERROR(ENOMEM);
     oggstream->header[0] = p;
     oggstream->header_len[0] = SPEEX_HEADER_SIZE;
-    bytestream_put_buffer(&p, avctx->extradata, SPEEX_HEADER_SIZE);
+    bytestream_put_buffer(&p, par->extradata, SPEEX_HEADER_SIZE);
     AV_WL32(&oggstream->header[0][68], 0);  // set extra_headers to 0
 
     // second packet: VorbisComment
@@ -361,22 +361,22 @@ static int ogg_build_speex_headers(AVCodecContext *avctx,
 
 #define OPUS_HEADER_SIZE 19
 
-static int ogg_build_opus_headers(AVCodecContext *avctx,
+static int ogg_build_opus_headers(AVCodecParameters *par,
                                   OGGStreamContext *oggstream, int bitexact,
                                   AVDictionary **m)
 {
     uint8_t *p;
 
-    if (avctx->extradata_size < OPUS_HEADER_SIZE)
+    if (par->extradata_size < OPUS_HEADER_SIZE)
         return -1;
 
     /* first packet: Opus header */
-    p = av_mallocz(avctx->extradata_size);
+    p = av_mallocz(par->extradata_size);
     if (!p)
         return AVERROR(ENOMEM);
     oggstream->header[0] = p;
-    oggstream->header_len[0] = avctx->extradata_size;
-    bytestream_put_buffer(&p, avctx->extradata, avctx->extradata_size);
+    oggstream->header_len[0] = par->extradata_size;
+    bytestream_put_buffer(&p, par->extradata, par->extradata_size);
 
     /* second packet: VorbisComment */
     p = ogg_write_vorbiscomment(8, bitexact, &oggstream->header_len[1], m, 0);
@@ -423,23 +423,23 @@ static int ogg_write_header(AVFormatContext *s)
         AVStream *st = s->streams[i];
         unsigned serial_num = i + ogg->serial_offset;
 
-        if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
-            if (st->codec->codec_id == AV_CODEC_ID_OPUS)
+        if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)
+            if (st->codecpar->codec_id == AV_CODEC_ID_OPUS)
                 /* Opus requires a fixed 48kHz clock */
                 avpriv_set_pts_info(st, 64, 1, 48000);
             else
-                avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
+                avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
 
-        if (st->codec->codec_id != AV_CODEC_ID_VORBIS &&
-            st->codec->codec_id != AV_CODEC_ID_THEORA &&
-            st->codec->codec_id != AV_CODEC_ID_SPEEX  &&
-            st->codec->codec_id != AV_CODEC_ID_FLAC   &&
-            st->codec->codec_id != AV_CODEC_ID_OPUS) {
+        if (st->codecpar->codec_id != AV_CODEC_ID_VORBIS &&
+            st->codecpar->codec_id != AV_CODEC_ID_THEORA &&
+            st->codecpar->codec_id != AV_CODEC_ID_SPEEX  &&
+            st->codecpar->codec_id != AV_CODEC_ID_FLAC   &&
+            st->codecpar->codec_id != AV_CODEC_ID_OPUS) {
             av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);
             return -1;
         }
 
-        if (!st->codec->extradata || !st->codec->extradata_size) {
+        if (!st->codecpar->extradata || !st->codecpar->extradata_size) {
             av_log(s, AV_LOG_ERROR, "No extradata present\n");
             return -1;
         }
@@ -460,8 +460,8 @@ static int ogg_write_header(AVFormatContext *s)
         oggstream->serial_num = serial_num;
 
         st->priv_data = oggstream;
-        if (st->codec->codec_id == AV_CODEC_ID_FLAC) {
-            int err = ogg_build_flac_headers(st->codec, oggstream,
+        if (st->codecpar->codec_id == AV_CODEC_ID_FLAC) {
+            int err = ogg_build_flac_headers(st->codecpar, oggstream,
                                              s->flags & AVFMT_FLAG_BITEXACT,
                                              &s->metadata);
             if (err) {
@@ -469,8 +469,8 @@ static int ogg_write_header(AVFormatContext *s)
                 av_freep(&st->priv_data);
                 return err;
             }
-        } else if (st->codec->codec_id == AV_CODEC_ID_SPEEX) {
-            int err = ogg_build_speex_headers(st->codec, oggstream,
+        } else if (st->codecpar->codec_id == AV_CODEC_ID_SPEEX) {
+            int err = ogg_build_speex_headers(st->codecpar, oggstream,
                                               s->flags & AVFMT_FLAG_BITEXACT,
                                               &s->metadata);
             if (err) {
@@ -478,8 +478,8 @@ static int ogg_write_header(AVFormatContext *s)
                 av_freep(&st->priv_data);
                 return err;
             }
-        } else if (st->codec->codec_id == AV_CODEC_ID_OPUS) {
-            int err = ogg_build_opus_headers(st->codec, oggstream,
+        } else if (st->codecpar->codec_id == AV_CODEC_ID_OPUS) {
+            int err = ogg_build_opus_headers(st->codecpar, oggstream,
                                              s->flags & AVFMT_FLAG_BITEXACT,
                                              &s->metadata);
             if (err) {
@@ -489,12 +489,12 @@ static int ogg_write_header(AVFormatContext *s)
             }
         } else {
             uint8_t *p;
-            const char *cstr = st->codec->codec_id == AV_CODEC_ID_VORBIS ? "vorbis" : "theora";
-            int header_type = st->codec->codec_id == AV_CODEC_ID_VORBIS ? 3 : 0x81;
-            int framing_bit = st->codec->codec_id == AV_CODEC_ID_VORBIS ? 1 : 0;
+            const char *cstr = st->codecpar->codec_id == AV_CODEC_ID_VORBIS ? "vorbis" : "theora";
+            int header_type = st->codecpar->codec_id == AV_CODEC_ID_VORBIS ? 3 : 0x81;
+            int framing_bit = st->codecpar->codec_id == AV_CODEC_ID_VORBIS ? 1 : 0;
 
-            if (avpriv_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,
-                                      st->codec->codec_id == AV_CODEC_ID_VORBIS ? 30 : 42,
+            if (avpriv_split_xiph_headers(st->codecpar->extradata, st->codecpar->extradata_size,
+                                      st->codecpar->codec_id == AV_CODEC_ID_VORBIS ? 30 : 42,
                                       oggstream->header, oggstream->header_len) < 0) {
                 av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
                 av_freep(&st->priv_data);
@@ -511,7 +511,7 @@ static int ogg_write_header(AVFormatContext *s)
             bytestream_put_byte(&p, header_type);
             bytestream_put_buffer(&p, cstr, 6);
 
-            if (st->codec->codec_id == AV_CODEC_ID_THEORA) {
+            if (st->codecpar->codec_id == AV_CODEC_ID_THEORA) {
                 /** KFGSHIFT is the width of the less significant section of the granule position
                     The less significant section is the frame count since the last keyframe */
                 oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);
@@ -554,7 +554,7 @@ static int ogg_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
     int ret;
     int64_t granule;
 
-    if (st->codec->codec_id == AV_CODEC_ID_THEORA) {
+    if (st->codecpar->codec_id == AV_CODEC_ID_THEORA) {
         int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;
         int pframe_count;
         if (pkt->flags & AV_PKT_FLAG_KEY)
@@ -566,10 +566,10 @@ static int ogg_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
             pframe_count = 0;
         }
         granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;
-    } else if (st->codec->codec_id == AV_CODEC_ID_OPUS)
+    } else if (st->codecpar->codec_id == AV_CODEC_ID_OPUS)
         granule = pkt->pts + pkt->duration +
-                  av_rescale_q(st->codec->initial_padding,
-                               (AVRational){ 1, st->codec->sample_rate },
+                  av_rescale_q(st->codecpar->initial_padding,
+                               (AVRational){ 1, st->codecpar->sample_rate },
                                st->time_base);
     else
         granule = pkt->pts + pkt->duration;
@@ -622,9 +622,9 @@ static int ogg_write_trailer(AVFormatContext *s)
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];
         OGGStreamContext *oggstream = st->priv_data;
-        if (st->codec->codec_id == AV_CODEC_ID_FLAC ||
-            st->codec->codec_id == AV_CODEC_ID_SPEEX ||
-            st->codec->codec_id == AV_CODEC_ID_OPUS) {
+        if (st->codecpar->codec_id == AV_CODEC_ID_FLAC ||
+            st->codecpar->codec_id == AV_CODEC_ID_SPEEX ||
+            st->codecpar->codec_id == AV_CODEC_ID_OPUS) {
             av_free(oggstream->header[0]);
         }
         av_freep(&oggstream->header[1]);