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, 31 insertions, 31 deletions

diff --git a/libavformat/gxfenc.c b/libavformat/gxfenc.c
index fea1d5d818..22ae315e2d 100644
--- a/libavformat/gxfenc.c
+++ b/libavformat/gxfenc.c
@@ -107,7 +107,7 @@ static int gxf_find_lines_index(AVStream *st)
     int i;
 
     for (i = 0; i < 6; ++i) {
-        if (st->codec->height == gxf_lines_tab[i].height) {
+        if (st->codecpar->height == gxf_lines_tab[i].height) {
             sc->lines_index = gxf_lines_tab[i].index;
             return 0;
         }
@@ -181,18 +181,18 @@ static int gxf_write_mpeg_auxiliary(AVIOContext *pb, AVStream *st)
         if (sc->b_per_i_or_p > 9)
             sc->b_per_i_or_p = 9; /* ensure value won't take more than one char */
     }
-    if (st->codec->height == 512 || st->codec->height == 608)
+    if (st->codecpar->height == 512 || st->codecpar->height == 608)
         starting_line = 7; // VBI
-    else if (st->codec->height == 480)
+    else if (st->codecpar->height == 480)
         starting_line = 20;
     else
         starting_line = 23; // default PAL
 
     size = snprintf(buffer, 1024, "Ver 1\nBr %.6f\nIpg 1\nPpi %d\nBpiop %d\n"
                     "Pix 0\nCf %d\nCg %d\nSl %d\nnl16 %d\nVi 1\nf1 1\n",
-                    (float)st->codec->bit_rate, sc->p_per_gop, sc->b_per_i_or_p,
-                    st->codec->pix_fmt == AV_PIX_FMT_YUV422P ? 2 : 1, sc->first_gop_closed == 1,
-                    starting_line, (st->codec->height + 15) / 16);
+                    (float)st->codecpar->bit_rate, sc->p_per_gop, sc->b_per_i_or_p,
+                    st->codecpar->format  == AV_PIX_FMT_YUV422P ? 2 : 1, sc->first_gop_closed == 1,
+                    starting_line, (st->codecpar->height + 15) / 16);
     avio_w8(pb, TRACK_MPG_AUX);
     avio_w8(pb, size + 1);
     avio_write(pb, (uint8_t *)buffer, size + 1);
@@ -472,7 +472,7 @@ static int gxf_write_umf_media_mpeg(AVIOContext *pb, AVStream *st)
 {
     GXFStreamContext *sc = st->priv_data;
 
-    if (st->codec->pix_fmt == AV_PIX_FMT_YUV422P)
+    if (st->codecpar->format == AV_PIX_FMT_YUV422P)
         avio_wl32(pb, 2);
     else
         avio_wl32(pb, 1); /* default to 420 */
@@ -481,9 +481,9 @@ static int gxf_write_umf_media_mpeg(AVIOContext *pb, AVStream *st)
     avio_wl32(pb, 1); /* I picture per GOP */
     avio_wl32(pb, sc->p_per_gop);
     avio_wl32(pb, sc->b_per_i_or_p);
-    if (st->codec->codec_id == AV_CODEC_ID_MPEG2VIDEO)
+    if (st->codecpar->codec_id == AV_CODEC_ID_MPEG2VIDEO)
         avio_wl32(pb, 2);
-    else if (st->codec->codec_id == AV_CODEC_ID_MPEG1VIDEO)
+    else if (st->codecpar->codec_id == AV_CODEC_ID_MPEG1VIDEO)
         avio_wl32(pb, 1);
     else
         avio_wl32(pb, 0);
@@ -565,7 +565,7 @@ static int gxf_write_umf_media_description(AVFormatContext *s)
             gxf_write_umf_media_timecode(pb, sc); /* 8 0bytes */
         else {
             AVStream *st = s->streams[i];
-            switch (st->codec->codec_id) {
+            switch (st->codecpar->codec_id) {
             case AV_CODEC_ID_MPEG1VIDEO:
             case AV_CODEC_ID_MPEG2VIDEO:
                 gxf_write_umf_media_mpeg(pb, st);
@@ -646,22 +646,22 @@ static int gxf_write_header(AVFormatContext *s)
             return AVERROR(ENOMEM);
         st->priv_data = sc;
 
-        sc->media_type = ff_codec_get_tag(gxf_media_types, st->codec->codec_id);
-        if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
-            if (st->codec->codec_id != AV_CODEC_ID_PCM_S16LE) {
+        sc->media_type = ff_codec_get_tag(gxf_media_types, st->codecpar->codec_id);
+        if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
+            if (st->codecpar->codec_id != AV_CODEC_ID_PCM_S16LE) {
                 av_log(s, AV_LOG_ERROR, "only 16 BIT PCM LE allowed for now\n");
                 return -1;
             }
-            if (st->codec->sample_rate != 48000) {
+            if (st->codecpar->sample_rate != 48000) {
                 av_log(s, AV_LOG_ERROR, "only 48000hz sampling rate is allowed\n");
                 return -1;
             }
-            if (st->codec->channels != 1) {
+            if (st->codecpar->channels != 1) {
                 av_log(s, AV_LOG_ERROR, "only mono tracks are allowed\n");
                 return -1;
             }
             sc->track_type = 2;
-            sc->sample_rate = st->codec->sample_rate;
+            sc->sample_rate = st->codecpar->sample_rate;
             avpriv_set_pts_info(st, 64, 1, sc->sample_rate);
             sc->sample_size = 16;
             sc->frame_rate_index = -2;
@@ -670,18 +670,18 @@ static int gxf_write_header(AVFormatContext *s)
             gxf->audio_tracks++;
             gxf->flags |= 0x04000000; /* audio is 16 bit pcm */
             media_info = 'A';
-        } else if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
+        } else if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
             if (i != 0) {
                 av_log(s, AV_LOG_ERROR, "video stream must be the first track\n");
                 return -1;
             }
             /* FIXME check from time_base ? */
-            if (st->codec->height == 480 || st->codec->height == 512) { /* NTSC or NTSC+VBI */
+            if (st->codecpar->height == 480 || st->codecpar->height == 512) { /* NTSC or NTSC+VBI */
                 sc->frame_rate_index = 5;
                 sc->sample_rate = 60;
                 gxf->flags |= 0x00000080;
                 gxf->time_base = (AVRational){ 1001, 60000 };
-            } else if (st->codec->height == 576 || st->codec->height == 608) { /* PAL or PAL+VBI */
+            } else if (st->codecpar->height == 576 || st->codecpar->height == 608) { /* PAL or PAL+VBI */
                 sc->frame_rate_index = 6;
                 sc->media_type++;
                 sc->sample_rate = 50;
@@ -695,12 +695,12 @@ static int gxf_write_header(AVFormatContext *s)
             avpriv_set_pts_info(st, 64, gxf->time_base.num, gxf->time_base.den);
             if (gxf_find_lines_index(st) < 0)
                 sc->lines_index = -1;
-            sc->sample_size = st->codec->bit_rate;
+            sc->sample_size = st->codecpar->bit_rate;
             sc->fields = 2; /* interlaced */
 
             vsc = sc;
 
-            switch (st->codec->codec_id) {
+            switch (st->codecpar->codec_id) {
             case AV_CODEC_ID_MJPEG:
                 sc->track_type = 1;
                 gxf->flags |= 0x00004000;
@@ -719,7 +719,7 @@ static int gxf_write_header(AVFormatContext *s)
                 media_info = 'M';
                 break;
             case AV_CODEC_ID_DVVIDEO:
-                if (st->codec->pix_fmt == AV_PIX_FMT_YUV422P) {
+                if (st->codecpar->format == AV_PIX_FMT_YUV422P) {
                     sc->media_type += 2;
                     sc->track_type = 6;
                     gxf->flags |= 0x00002000;
@@ -818,7 +818,7 @@ static int gxf_write_media_preamble(AVFormatContext *s, AVPacket *pkt, int size)
     /* If the video is frame-encoded, the frame numbers shall be represented by
      * even field numbers.
      * see SMPTE360M-2004  6.4.2.1.3 Media field number */
-    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
+    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
         field_nb = gxf->nb_fields;
     } else {
         field_nb = av_rescale_rnd(pkt->dts, gxf->time_base.den,
@@ -828,10 +828,10 @@ static int gxf_write_media_preamble(AVFormatContext *s, AVPacket *pkt, int size)
     avio_w8(pb, sc->media_type);
     avio_w8(pb, st->index);
     avio_wb32(pb, field_nb);
-    if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
+    if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
         avio_wb16(pb, 0);
         avio_wb16(pb, size / 2);
-    } else if (st->codec->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
+    } else if (st->codecpar->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
         int frame_type = gxf_parse_mpeg_frame(sc, pkt->data, pkt->size);
         if (frame_type == AV_PICTURE_TYPE_I) {
             avio_w8(pb, 0x0d);
@@ -844,7 +844,7 @@ static int gxf_write_media_preamble(AVFormatContext *s, AVPacket *pkt, int size)
             sc->pframes++;
         }
         avio_wb24(pb, size);
-    } else if (st->codec->codec_id == AV_CODEC_ID_DVVIDEO) {
+    } else if (st->codecpar->codec_id == AV_CODEC_ID_DVVIDEO) {
         avio_w8(pb, size / 4096);
         avio_wb24(pb, 0);
     } else
@@ -865,15 +865,15 @@ static int gxf_write_packet(AVFormatContext *s, AVPacket *pkt)
     int packet_start_offset = avio_tell(pb) / 1024;
 
     gxf_write_packet_header(pb, PKT_MEDIA);
-    if (st->codec->codec_id == AV_CODEC_ID_MPEG2VIDEO && pkt->size % 4) /* MPEG-2 frames must be padded */
+    if (st->codecpar->codec_id == AV_CODEC_ID_MPEG2VIDEO && pkt->size % 4) /* MPEG-2 frames must be padded */
         padding = 4 - pkt->size % 4;
-    else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
+    else if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)
         padding = GXF_AUDIO_PACKET_SIZE - pkt->size;
     gxf_write_media_preamble(s, pkt, pkt->size + padding);
     avio_write(pb, pkt->data, pkt->size);
     gxf_write_padding(pb, padding);
 
-    if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
+    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
         if (!(gxf->flt_entries_nb % 500)) {
             int err;
             if ((err = av_reallocp_array(&gxf->flt_entries,
@@ -909,7 +909,7 @@ static int gxf_compare_field_nb(AVFormatContext *s, AVPacket *next, AVPacket *cu
     for (i = 0; i < 2; i++) {
         AVStream *st = s->streams[pkt[i]->stream_index];
         sc[i] = st->priv_data;
-        if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
+        if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
             field_nb[i] = av_rescale_rnd(pkt[i]->dts, gxf->time_base.den,
                                          (int64_t)48000*gxf->time_base.num, AV_ROUND_UP);
             field_nb[i] &= ~1; // compare against even field number because audio must be before video
@@ -923,7 +923,7 @@ static int gxf_compare_field_nb(AVFormatContext *s, AVPacket *next, AVPacket *cu
 
 static int gxf_interleave_packet(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush)
 {
-    if (pkt && s->streams[pkt->stream_index]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
+    if (pkt && s->streams[pkt->stream_index]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
         pkt->duration = 2; // enforce 2 fields
     return ff_audio_rechunk_interleave(s, out, pkt, flush,
                                ff_interleave_packet_per_dts, gxf_compare_field_nb);