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, 45 insertions, 45 deletions

diff --git a/libavformat/swfenc.c b/libavformat/swfenc.c
index 877c847acb..f8db3e9196 100644
--- a/libavformat/swfenc.c
+++ b/libavformat/swfenc.c
@@ -184,14 +184,14 @@ static int swf_write_header(AVFormatContext *s)
     swf->video_frame_number = 0;
 
     for(i=0;i<s->nb_streams;i++) {
-        AVCodecContext *enc = s->streams[i]->codec;
-        if (enc->codec_type == AVMEDIA_TYPE_AUDIO) {
-            if (swf->audio_enc) {
+        AVCodecParameters *par = s->streams[i]->codecpar;
+        if (par->codec_type == AVMEDIA_TYPE_AUDIO) {
+            if (swf->audio_par) {
                 av_log(s, AV_LOG_ERROR, "SWF muxer only supports 1 audio stream\n");
                 return AVERROR_INVALIDDATA;
             }
-            if (enc->codec_id == AV_CODEC_ID_MP3) {
-                swf->audio_enc = enc;
+            if (par->codec_id == AV_CODEC_ID_MP3) {
+                swf->audio_par = par;
                 swf->audio_fifo= av_fifo_alloc(AUDIO_FIFO_SIZE);
                 if (!swf->audio_fifo)
                     return AVERROR(ENOMEM);
@@ -200,15 +200,15 @@ static int swf_write_header(AVFormatContext *s)
                 return -1;
             }
         } else {
-            if (swf->video_enc) {
+            if (swf->video_par) {
                 av_log(s, AV_LOG_ERROR, "SWF muxer only supports 1 video stream\n");
                 return AVERROR_INVALIDDATA;
             }
-            if (enc->codec_id == AV_CODEC_ID_VP6F ||
-                enc->codec_id == AV_CODEC_ID_FLV1 ||
-                enc->codec_id == AV_CODEC_ID_MJPEG) {
+            if (par->codec_id == AV_CODEC_ID_VP6F ||
+                par->codec_id == AV_CODEC_ID_FLV1 ||
+                par->codec_id == AV_CODEC_ID_MJPEG) {
                 swf->video_st  = s->streams[i];
-                swf->video_enc = enc;
+                swf->video_par = par;
             } else {
                 av_log(s, AV_LOG_ERROR, "SWF muxer only supports VP6, FLV1 and MJPEG\n");
                 return -1;
@@ -216,32 +216,32 @@ static int swf_write_header(AVFormatContext *s)
         }
     }
 
-    if (!swf->video_enc) {
+    if (!swf->video_par) {
         /* currently, cannot work correctly if audio only */
         width = 320;
         height = 200;
         rate = 10;
         rate_base= 1;
     } else {
-        width = swf->video_enc->width;
-        height = swf->video_enc->height;
+        width = swf->video_par->width;
+        height = swf->video_par->height;
         // TODO: should be avg_frame_rate
         rate = swf->video_st->time_base.den;
         rate_base = swf->video_st->time_base.num;
     }
 
-    if (!swf->audio_enc)
+    if (!swf->audio_par)
         swf->samples_per_frame = (44100.0 * rate_base) / rate;
     else
-        swf->samples_per_frame = (swf->audio_enc->sample_rate * rate_base) / rate;
+        swf->samples_per_frame = (swf->audio_par->sample_rate * rate_base) / rate;
 
     avio_write(pb, "FWS", 3);
 
     if (!strcmp("avm2", s->oformat->name))
         version = 9;
-    else if (swf->video_enc && swf->video_enc->codec_id == AV_CODEC_ID_VP6F)
+    else if (swf->video_par && swf->video_par->codec_id == AV_CODEC_ID_VP6F)
         version = 8; /* version 8 and above support VP6 codec */
-    else if (swf->video_enc && swf->video_enc->codec_id == AV_CODEC_ID_FLV1)
+    else if (swf->video_par && swf->video_par->codec_id == AV_CODEC_ID_FLV1)
         version = 6; /* version 6 and above support FLV1 codec */
     else
         version = 4; /* version 4 for mpeg audio support */
@@ -263,7 +263,7 @@ static int swf_write_header(AVFormatContext *s)
     }
 
     /* define a shape with the jpeg inside */
-    if (swf->video_enc && swf->video_enc->codec_id == AV_CODEC_ID_MJPEG) {
+    if (swf->video_par && swf->video_par->codec_id == AV_CODEC_ID_MJPEG) {
         put_swf_tag(s, TAG_DEFINESHAPE);
 
         avio_wl16(pb, SHAPE_ID); /* ID of shape */
@@ -306,12 +306,12 @@ static int swf_write_header(AVFormatContext *s)
         put_swf_end_tag(s);
     }
 
-    if (swf->audio_enc && swf->audio_enc->codec_id == AV_CODEC_ID_MP3) {
+    if (swf->audio_par && swf->audio_par->codec_id == AV_CODEC_ID_MP3) {
         int v = 0;
 
         /* start sound */
         put_swf_tag(s, TAG_STREAMHEAD2);
-        switch(swf->audio_enc->sample_rate) {
+        switch(swf->audio_par->sample_rate) {
         case 11025: v |= 1 << 2; break;
         case 22050: v |= 2 << 2; break;
         case 44100: v |= 3 << 2; break;
@@ -321,7 +321,7 @@ static int swf_write_header(AVFormatContext *s)
             return -1;
         }
         v |= 0x02; /* 16 bit playback */
-        if (swf->audio_enc->channels == 2)
+        if (swf->audio_par->channels == 2)
             v |= 0x01; /* stereo playback */
         avio_w8(s->pb, v);
         v |= 0x20; /* mp3 compressed */
@@ -337,27 +337,27 @@ static int swf_write_header(AVFormatContext *s)
 }
 
 static int swf_write_video(AVFormatContext *s,
-                           AVCodecContext *enc, const uint8_t *buf, int size)
+                           AVCodecParameters *par, const uint8_t *buf, int size)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *pb = s->pb;
 
     /* Flash Player limit */
     if (swf->swf_frame_number == 16000)
-        av_log(enc, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");
+        av_log(s, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");
 
-    if (enc->codec_id == AV_CODEC_ID_VP6F ||
-        enc->codec_id == AV_CODEC_ID_FLV1) {
+    if (par->codec_id == AV_CODEC_ID_VP6F ||
+        par->codec_id == AV_CODEC_ID_FLV1) {
         if (swf->video_frame_number == 0) {
             /* create a new video object */
             put_swf_tag(s, TAG_VIDEOSTREAM);
             avio_wl16(pb, VIDEO_ID);
             swf->vframes_pos = avio_tell(pb);
             avio_wl16(pb, 15000); /* hard flash player limit */
-            avio_wl16(pb, enc->width);
-            avio_wl16(pb, enc->height);
+            avio_wl16(pb, par->width);
+            avio_wl16(pb, par->height);
             avio_w8(pb, 0);
-            avio_w8(pb,ff_codec_get_tag(ff_swf_codec_tags, enc->codec_id));
+            avio_w8(pb,ff_codec_get_tag(ff_swf_codec_tags, par->codec_id));
             put_swf_end_tag(s);
 
             /* place the video object for the first time */
@@ -385,7 +385,7 @@ static int swf_write_video(AVFormatContext *s,
         avio_wl16(pb, swf->video_frame_number++);
         avio_write(pb, buf, size);
         put_swf_end_tag(s);
-    } else if (enc->codec_id == AV_CODEC_ID_MJPEG) {
+    } else if (par->codec_id == AV_CODEC_ID_MJPEG) {
         if (swf->swf_frame_number > 0) {
             /* remove the shape */
             put_swf_tag(s, TAG_REMOVEOBJECT);
@@ -422,7 +422,7 @@ static int swf_write_video(AVFormatContext *s,
     swf->swf_frame_number++;
 
     /* streaming sound always should be placed just before showframe tags */
-    if (swf->audio_enc && av_fifo_size(swf->audio_fifo)) {
+    if (swf->audio_par && av_fifo_size(swf->audio_fifo)) {
         int frame_size = av_fifo_size(swf->audio_fifo);
         put_swf_tag(s, TAG_STREAMBLOCK | TAG_LONG);
         avio_wl16(pb, swf->sound_samples);
@@ -443,13 +443,13 @@ static int swf_write_video(AVFormatContext *s,
 }
 
 static int swf_write_audio(AVFormatContext *s,
-                           AVCodecContext *enc, uint8_t *buf, int size)
+                           AVCodecParameters *par, uint8_t *buf, int size)
 {
     SWFContext *swf = s->priv_data;
 
     /* Flash Player limit */
     if (swf->swf_frame_number == 16000)
-        av_log(enc, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");
+        av_log(s, AV_LOG_INFO, "warning: Flash Player limit of 16000 frames reached\n");
 
     if (av_fifo_size(swf->audio_fifo) + size > AUDIO_FIFO_SIZE) {
         av_log(s, AV_LOG_ERROR, "audio fifo too small to mux audio essence\n");
@@ -457,36 +457,36 @@ static int swf_write_audio(AVFormatContext *s,
     }
 
     av_fifo_generic_write(swf->audio_fifo, buf, size, NULL);
-    swf->sound_samples += av_get_audio_frame_duration(enc, size);
+    swf->sound_samples += av_get_audio_frame_duration2(par, size);
 
     /* if audio only stream make sure we add swf frames */
-    if (!swf->video_enc)
-        swf_write_video(s, enc, 0, 0);
+    if (!swf->video_par)
+        swf_write_video(s, par, 0, 0);
 
     return 0;
 }
 
 static int swf_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
-    AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
-    if (codec->codec_type == AVMEDIA_TYPE_AUDIO)
-        return swf_write_audio(s, codec, pkt->data, pkt->size);
+    AVCodecParameters *par = s->streams[pkt->stream_index]->codecpar;
+    if (par->codec_type == AVMEDIA_TYPE_AUDIO)
+        return swf_write_audio(s, par, pkt->data, pkt->size);
     else
-        return swf_write_video(s, codec, pkt->data, pkt->size);
+        return swf_write_video(s, par, pkt->data, pkt->size);
 }
 
 static int swf_write_trailer(AVFormatContext *s)
 {
     SWFContext *swf = s->priv_data;
     AVIOContext *pb = s->pb;
-    AVCodecContext *enc, *video_enc;
+    AVCodecParameters *par, *video_par;
     int file_size, i;
 
-    video_enc = NULL;
+    video_par = NULL;
     for(i=0;i<s->nb_streams;i++) {
-        enc = s->streams[i]->codec;
-        if (enc->codec_type == AVMEDIA_TYPE_VIDEO)
-            video_enc = enc;
+        par = s->streams[i]->codecpar;
+        if (par->codec_type == AVMEDIA_TYPE_VIDEO)
+            video_par = par;
         else
             av_fifo_free(swf->audio_fifo);
     }
@@ -495,7 +495,7 @@ static int swf_write_trailer(AVFormatContext *s)
     put_swf_end_tag(s);
 
     /* patch file size and number of frames if not streamed */
-    if (s->pb->seekable && video_enc) {
+    if (s->pb->seekable && video_par) {
         file_size = avio_tell(pb);
         avio_seek(pb, 4, SEEK_SET);
         avio_wl32(pb, file_size);