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, 76 insertions, 76 deletions

diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
index 49c52357e2..2dfe3ae867 100644
--- a/libavformat/flvenc.c
+++ b/libavformat/flvenc.c
@@ -61,37 +61,37 @@ typedef struct FLVContext {
     int64_t duration;
     int64_t delay;      ///< first dts delay (needed for AVC & Speex)
 
-    AVCodecContext *audio_enc;
-    AVCodecContext *video_enc;
+    AVCodecParameters *audio_par;
+    AVCodecParameters *video_par;
     double framerate;
-    AVCodecContext *data_enc;
+    AVCodecParameters *data_par;
 } FLVContext;
 
 typedef struct FLVStreamContext {
     int64_t last_ts;    ///< last timestamp for each stream
 } FLVStreamContext;
 
-static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
+static int get_audio_flags(AVFormatContext *s, AVCodecParameters *par)
 {
-    int flags = (enc->bits_per_coded_sample == 16) ? FLV_SAMPLESSIZE_16BIT
+    int flags = (par->bits_per_coded_sample == 16) ? FLV_SAMPLESSIZE_16BIT
                                                    : FLV_SAMPLESSIZE_8BIT;
 
-    if (enc->codec_id == AV_CODEC_ID_AAC) // specs force these parameters
+    if (par->codec_id == AV_CODEC_ID_AAC) // specs force these parameters
         return FLV_CODECID_AAC | FLV_SAMPLERATE_44100HZ |
                FLV_SAMPLESSIZE_16BIT | FLV_STEREO;
-    else if (enc->codec_id == AV_CODEC_ID_SPEEX) {
-        if (enc->sample_rate != 16000) {
+    else if (par->codec_id == AV_CODEC_ID_SPEEX) {
+        if (par->sample_rate != 16000) {
             av_log(s, AV_LOG_ERROR,
                    "flv only supports wideband (16kHz) Speex audio\n");
             return -1;
         }
-        if (enc->channels != 1) {
+        if (par->channels != 1) {
             av_log(s, AV_LOG_ERROR, "flv only supports mono Speex audio\n");
             return -1;
         }
         return FLV_CODECID_SPEEX | FLV_SAMPLERATE_11025HZ | FLV_SAMPLESSIZE_16BIT;
     } else {
-        switch (enc->sample_rate) {
+        switch (par->sample_rate) {
         case 44100:
             flags |= FLV_SAMPLERATE_44100HZ;
             break;
@@ -104,7 +104,7 @@ static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
         case 16000: // nellymoser only
         case  8000: // nellymoser only
         case  5512: // not MP3
-            if (enc->codec_id != AV_CODEC_ID_MP3) {
+            if (par->codec_id != AV_CODEC_ID_MP3) {
                 flags |= FLV_SAMPLERATE_SPECIAL;
                 break;
             }
@@ -116,10 +116,10 @@ static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
         }
     }
 
-    if (enc->channels > 1)
+    if (par->channels > 1)
         flags |= FLV_STEREO;
 
-    switch (enc->codec_id) {
+    switch (par->codec_id) {
     case AV_CODEC_ID_MP3:
         flags |= FLV_CODECID_MP3    | FLV_SAMPLESSIZE_16BIT;
         break;
@@ -136,9 +136,9 @@ static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
         flags |= FLV_CODECID_ADPCM  | FLV_SAMPLESSIZE_16BIT;
         break;
     case AV_CODEC_ID_NELLYMOSER:
-        if (enc->sample_rate == 8000)
+        if (par->sample_rate == 8000)
             flags |= FLV_CODECID_NELLYMOSER_8KHZ_MONO  | FLV_SAMPLESSIZE_16BIT;
-        else if (enc->sample_rate == 16000)
+        else if (par->sample_rate == 16000)
             flags |= FLV_CODECID_NELLYMOSER_16KHZ_MONO | FLV_SAMPLESSIZE_16BIT;
         else
             flags |= FLV_CODECID_NELLYMOSER            | FLV_SAMPLESSIZE_16BIT;
@@ -150,7 +150,7 @@ static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
         flags = FLV_CODECID_PCM_ALAW  | FLV_SAMPLERATE_SPECIAL | FLV_SAMPLESSIZE_16BIT;
         break;
     case 0:
-        flags |= enc->codec_tag << 4;
+        flags |= par->codec_tag << 4;
         break;
     default:
         av_log(s, AV_LOG_ERROR, "codec not compatible with flv\n");
@@ -216,9 +216,9 @@ static void write_metadata(AVFormatContext *s, unsigned int ts)
     /* mixed array (hash) with size and string/type/data tuples */
     avio_w8(pb, AMF_DATA_TYPE_MIXEDARRAY);
     metadata_count_pos = avio_tell(pb);
-    metadata_count = 4 * !!flv->video_enc +
-                     5 * !!flv->audio_enc +
-                     1 * !!flv->data_enc  +
+    metadata_count = 4 * !!flv->video_par +
+                     5 * !!flv->audio_par +
+                     1 * !!flv->data_par  +
                      2; // +2 for duration and file size
 
     avio_wb32(pb, metadata_count);
@@ -229,15 +229,15 @@ static void write_metadata(AVFormatContext *s, unsigned int ts)
     // fill in the guessed duration, it'll be corrected later if incorrect
     put_amf_double(pb, s->duration / AV_TIME_BASE);
 
-    if (flv->video_enc) {
+    if (flv->video_par) {
         put_amf_string(pb, "width");
-        put_amf_double(pb, flv->video_enc->width);
+        put_amf_double(pb, flv->video_par->width);
 
         put_amf_string(pb, "height");
-        put_amf_double(pb, flv->video_enc->height);
+        put_amf_double(pb, flv->video_par->height);
 
         put_amf_string(pb, "videodatarate");
-        put_amf_double(pb, flv->video_enc->bit_rate / 1024.0);
+        put_amf_double(pb, flv->video_par->bit_rate / 1024.0);
 
         if (flv->framerate != 0.0) {
             put_amf_string(pb, "framerate");
@@ -246,27 +246,27 @@ static void write_metadata(AVFormatContext *s, unsigned int ts)
         }
 
         put_amf_string(pb, "videocodecid");
-        put_amf_double(pb, flv->video_enc->codec_tag);
+        put_amf_double(pb, flv->video_par->codec_tag);
     }
 
-    if (flv->audio_enc) {
+    if (flv->audio_par) {
         put_amf_string(pb, "audiodatarate");
-        put_amf_double(pb, flv->audio_enc->bit_rate / 1024.0);
+        put_amf_double(pb, flv->audio_par->bit_rate / 1024.0);
 
         put_amf_string(pb, "audiosamplerate");
-        put_amf_double(pb, flv->audio_enc->sample_rate);
+        put_amf_double(pb, flv->audio_par->sample_rate);
 
         put_amf_string(pb, "audiosamplesize");
-        put_amf_double(pb, flv->audio_enc->codec_id == AV_CODEC_ID_PCM_U8 ? 8 : 16);
+        put_amf_double(pb, flv->audio_par->codec_id == AV_CODEC_ID_PCM_U8 ? 8 : 16);
 
         put_amf_string(pb, "stereo");
-        put_amf_bool(pb, flv->audio_enc->channels == 2);
+        put_amf_bool(pb, flv->audio_par->channels == 2);
 
         put_amf_string(pb, "audiocodecid");
-        put_amf_double(pb, flv->audio_enc->codec_tag);
+        put_amf_double(pb, flv->audio_par->codec_tag);
     }
 
-    if (flv->data_enc) {
+    if (flv->data_par) {
         put_amf_string(pb, "datastream");
         put_amf_double(pb, 0.0);
     }
@@ -316,37 +316,37 @@ static int flv_write_header(AVFormatContext *s)
     int64_t data_size;
 
     for (i = 0; i < s->nb_streams; i++) {
-        AVCodecContext *enc = s->streams[i]->codec;
+        AVCodecParameters *par = s->streams[i]->codecpar;
         FLVStreamContext *sc;
-        switch (enc->codec_type) {
+        switch (par->codec_type) {
         case AVMEDIA_TYPE_VIDEO:
             if (s->streams[i]->avg_frame_rate.den &&
                 s->streams[i]->avg_frame_rate.num) {
                 flv->framerate = av_q2d(s->streams[i]->avg_frame_rate);
             }
-            if (flv->video_enc) {
+            if (flv->video_par) {
                 av_log(s, AV_LOG_ERROR,
                        "at most one video stream is supported in flv\n");
                 return AVERROR(EINVAL);
             }
-            flv->video_enc = enc;
-            if (!ff_codec_get_tag(flv_video_codec_ids, enc->codec_id))
-                return unsupported_codec(s, "Video", enc->codec_id);
+            flv->video_par = par;
+            if (!ff_codec_get_tag(flv_video_codec_ids, par->codec_id))
+                return unsupported_codec(s, "Video", par->codec_id);
             break;
         case AVMEDIA_TYPE_AUDIO:
-            if (flv->audio_enc) {
+            if (flv->audio_par) {
                 av_log(s, AV_LOG_ERROR,
                        "at most one audio stream is supported in flv\n");
                 return AVERROR(EINVAL);
             }
-            flv->audio_enc = enc;
-            if (get_audio_flags(s, enc) < 0)
-                return unsupported_codec(s, "Audio", enc->codec_id);
+            flv->audio_par = par;
+            if (get_audio_flags(s, par) < 0)
+                return unsupported_codec(s, "Audio", par->codec_id);
             break;
         case AVMEDIA_TYPE_DATA:
-            if (enc->codec_id != AV_CODEC_ID_TEXT)
-                return unsupported_codec(s, "Data", enc->codec_id);
-            flv->data_enc = enc;
+            if (par->codec_id != AV_CODEC_ID_TEXT)
+                return unsupported_codec(s, "Data", par->codec_id);
+            flv->data_par = par;
             break;
         default:
             av_log(s, AV_LOG_ERROR, "codec not compatible with flv\n");
@@ -365,13 +365,13 @@ static int flv_write_header(AVFormatContext *s)
 
     avio_write(pb, "FLV", 3);
     avio_w8(pb, 1);
-    avio_w8(pb, FLV_HEADER_FLAG_HASAUDIO * !!flv->audio_enc +
-                FLV_HEADER_FLAG_HASVIDEO * !!flv->video_enc);
+    avio_w8(pb, FLV_HEADER_FLAG_HASAUDIO * !!flv->audio_par +
+                FLV_HEADER_FLAG_HASVIDEO * !!flv->video_par);
     avio_wb32(pb, 9);
     avio_wb32(pb, 0);
 
     for (i = 0; i < s->nb_streams; i++)
-        if (s->streams[i]->codec->codec_tag == 5) {
+        if (s->streams[i]->codecpar->codec_tag == 5) {
             avio_w8(pb, 8);     // message type
             avio_wb24(pb, 0);   // include flags
             avio_wb24(pb, 0);   // time stamp
@@ -383,25 +383,25 @@ static int flv_write_header(AVFormatContext *s)
     write_metadata(s, 0);
 
     for (i = 0; i < s->nb_streams; i++) {
-        AVCodecContext *enc = s->streams[i]->codec;
-        if (enc->codec_id == AV_CODEC_ID_AAC || enc->codec_id == AV_CODEC_ID_H264) {
+        AVCodecParameters *par = s->streams[i]->codecpar;
+        if (par->codec_id == AV_CODEC_ID_AAC || par->codec_id == AV_CODEC_ID_H264) {
             int64_t pos;
-            avio_w8(pb, enc->codec_type == AVMEDIA_TYPE_VIDEO ?
+            avio_w8(pb, par->codec_type == AVMEDIA_TYPE_VIDEO ?
                     FLV_TAG_TYPE_VIDEO : FLV_TAG_TYPE_AUDIO);
             avio_wb24(pb, 0); // size patched later
             avio_wb24(pb, 0); // ts
             avio_w8(pb, 0);   // ts ext
             avio_wb24(pb, 0); // streamid
             pos = avio_tell(pb);
-            if (enc->codec_id == AV_CODEC_ID_AAC) {
-                avio_w8(pb, get_audio_flags(s, enc));
+            if (par->codec_id == AV_CODEC_ID_AAC) {
+                avio_w8(pb, get_audio_flags(s, par));
                 avio_w8(pb, 0); // AAC sequence header
-                avio_write(pb, enc->extradata, enc->extradata_size);
+                avio_write(pb, par->extradata, par->extradata_size);
             } else {
-                avio_w8(pb, enc->codec_tag | FLV_FRAME_KEY); // flags
+                avio_w8(pb, par->codec_tag | FLV_FRAME_KEY); // flags
                 avio_w8(pb, 0); // AVC sequence header
                 avio_wb24(pb, 0); // composition time
-                ff_isom_write_avcc(pb, enc->extradata, enc->extradata_size);
+                ff_isom_write_avcc(pb, par->extradata, par->extradata_size);
             }
             data_size = avio_tell(pb) - pos;
             avio_seek(pb, -data_size - 10, SEEK_CUR);
@@ -424,10 +424,10 @@ static int flv_write_trailer(AVFormatContext *s)
 
     /* Add EOS tag */
     for (i = 0; i < s->nb_streams; i++) {
-        AVCodecContext *enc = s->streams[i]->codec;
+        AVCodecParameters *par = s->streams[i]->codecpar;
         FLVStreamContext *sc = s->streams[i]->priv_data;
-        if (enc->codec_type == AVMEDIA_TYPE_VIDEO &&
-            enc->codec_id == AV_CODEC_ID_H264)
+        if (par->codec_type == AVMEDIA_TYPE_VIDEO &&
+            par->codec_id == AV_CODEC_ID_H264)
             put_avc_eos_tag(pb, sc->last_ts);
     }
 
@@ -450,7 +450,7 @@ static int flv_write_trailer(AVFormatContext *s)
 static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     AVIOContext *pb      = s->pb;
-    AVCodecContext *enc  = s->streams[pkt->stream_index]->codec;
+    AVCodecParameters *par = s->streams[pkt->stream_index]->codecpar;
     FLVContext *flv      = s->priv_data;
     FLVStreamContext *sc = s->streams[pkt->stream_index]->priv_data;
     unsigned ts;
@@ -458,10 +458,10 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
     uint8_t *data = NULL;
     int flags = 0, flags_size;
 
-    if (enc->codec_id == AV_CODEC_ID_VP6F || enc->codec_id == AV_CODEC_ID_VP6A ||
-        enc->codec_id == AV_CODEC_ID_AAC)
+    if (par->codec_id == AV_CODEC_ID_VP6F || par->codec_id == AV_CODEC_ID_VP6A ||
+        par->codec_id == AV_CODEC_ID_AAC)
         flags_size = 2;
-    else if (enc->codec_id == AV_CODEC_ID_H264)
+    else if (par->codec_id == AV_CODEC_ID_H264)
         flags_size = 5;
     else
         flags_size = 1;
@@ -482,16 +482,16 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
         s->event_flags &= ~AVSTREAM_EVENT_FLAG_METADATA_UPDATED;
     }
 
-    switch (enc->codec_type) {
+    switch (par->codec_type) {
     case AVMEDIA_TYPE_VIDEO:
         avio_w8(pb, FLV_TAG_TYPE_VIDEO);
 
-        flags = ff_codec_get_tag(flv_video_codec_ids, enc->codec_id);
+        flags = ff_codec_get_tag(flv_video_codec_ids, par->codec_id);
 
         flags |= pkt->flags & AV_PKT_FLAG_KEY ? FLV_FRAME_KEY : FLV_FRAME_INTER;
         break;
     case AVMEDIA_TYPE_AUDIO:
-        flags = get_audio_flags(s, enc);
+        flags = get_audio_flags(s, par);
 
         assert(size);
 
@@ -504,14 +504,14 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
         return AVERROR(EINVAL);
     }
 
-    if (enc->codec_id == AV_CODEC_ID_H264)
+    if (par->codec_id == AV_CODEC_ID_H264)
         /* check if extradata looks like MP4 */
-        if (enc->extradata_size > 0 && *(uint8_t*)enc->extradata != 1)
+        if (par->extradata_size > 0 && *(uint8_t*)par->extradata != 1)
             if (ff_avc_parse_nal_units_buf(pkt->data, &data, &size) < 0)
                 return -1;
 
     /* check Speex packet duration */
-    if (enc->codec_id == AV_CODEC_ID_SPEEX && ts - sc->last_ts > 160)
+    if (par->codec_id == AV_CODEC_ID_SPEEX && ts - sc->last_ts > 160)
         av_log(s, AV_LOG_WARNING, "Warning: Speex stream has more than "
                                   "8 frames per packet. Adobe Flash "
                                   "Player cannot handle this!\n");
@@ -524,7 +524,7 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
     avio_w8(pb, (ts >> 24) & 0x7F); // timestamps are 32 bits _signed_
     avio_wb24(pb, flv->reserved);
 
-    if (enc->codec_type == AVMEDIA_TYPE_DATA) {
+    if (par->codec_type == AVMEDIA_TYPE_DATA) {
         int data_size;
         int64_t metadata_size_pos = avio_tell(pb);
         avio_w8(pb, AMF_DATA_TYPE_STRING);
@@ -547,15 +547,15 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
         avio_wb32(pb, data_size + 11);
     } else {
         avio_w8(pb,flags);
-        if (enc->codec_id == AV_CODEC_ID_VP6F || enc->codec_id == AV_CODEC_ID_VP6A) {
-            if (enc->extradata_size)
-                avio_w8(pb, enc->extradata[0]);
+        if (par->codec_id == AV_CODEC_ID_VP6F || par->codec_id == AV_CODEC_ID_VP6A) {
+            if (par->extradata_size)
+                avio_w8(pb, par->extradata[0]);
             else
-                avio_w8(pb, ((FFALIGN(enc->width,  16) - enc->width) << 4) |
-                             (FFALIGN(enc->height, 16) - enc->height));
-        } else if (enc->codec_id == AV_CODEC_ID_AAC)
+                avio_w8(pb, ((FFALIGN(par->width,  16) - par->width) << 4) |
+                             (FFALIGN(par->height, 16) - par->height));
+        } else if (par->codec_id == AV_CODEC_ID_AAC)
             avio_w8(pb, 1); // AAC raw
-        else if (enc->codec_id == AV_CODEC_ID_H264) {
+        else if (par->codec_id == AV_CODEC_ID_H264) {
             avio_w8(pb, 1); // AVC NALU
             avio_wb24(pb, pkt->pts - pkt->dts);
         }