lavf: add avformat_write_header() as a replacement for av_write_header().

It supports more convenient setting of AVOptions.

libavformat/avformat.h

@@ -1322,7 +1322,12 @@ int64_t av_gen_search(AVFormatContext *s, int stream_index,
 /**
  * media file output
  */
-int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap);
+#if FF_API_FORMAT_PARAMETERS
+/**
+ * @deprecated pass the options to avformat_write_header directly.
+ */
+attribute_deprecated int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap);
+#endif
 
 /**
  * Split a URL string into components.
@@ -1350,6 +1355,24 @@ void av_url_split(char *proto,         int proto_size,
                   char *path,          int path_size,
                   const char *url);
 
+/**
+ * Allocate the stream private data and write the stream header to
+ * an output media file.
+ *
+ * @param s Media file handle, must be allocated with avformat_alloc_context().
+ *          Its oformat field must be set to the desired output format;
+ *          Its pb field must be set to an already openened AVIOContext.
+ * @param options  An AVDictionary filled with AVFormatContext and muxer-private options.
+ *                 On return this parameter will be destroyed and replaced with a dict containing
+ *                 options that were not found. May be NULL.
+ *
+ * @return 0 on success, negative AVERROR on failure.
+ *
+ * @see av_opt_find, av_dict_set, avio_open, av_oformat_next.
+ */
+int avformat_write_header(AVFormatContext *s, AVDictionary **options);
+
+#if FF_API_FORMAT_PARAMETERS
 /**
  * Allocate the stream private data and write the stream header to an
  * output media file.
@@ -1358,8 +1381,11 @@ void av_url_split(char *proto,         int proto_size,
  *
  * @param s media file handle
  * @return 0 if OK, AVERROR_xxx on error
+ *
+ * @deprecated use avformat_write_header.
  */
-int av_write_header(AVFormatContext *s);
+attribute_deprecated int av_write_header(AVFormatContext *s);
+#endif
 
 /**
  * Write a packet to an output media file.

libavformat/rtpenc_chain.c

@@ -66,7 +66,7 @@ AVFormatContext *ff_rtp_chain_mux_open(AVFormatContext *s, AVStream *st,
         ffio_fdopen(&rtpctx->pb, handle);
     } else
         ffio_open_dyn_packet_buf(&rtpctx->pb, packet_size);
-    ret = av_write_header(rtpctx);
+    ret = avformat_write_header(rtpctx, NULL);
 
     if (ret) {
         if (handle) {

libavformat/utils.c

@@ -2733,6 +2733,7 @@ AVChapter *ff_new_chapter(AVFormatContext *s, int id, AVRational time_base, int6
 /************************************************************/
 /* output media file */
 
+#if FF_API_FORMAT_PARAMETERS
 int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap)
 {
     int ret;
@@ -2755,6 +2756,7 @@ int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap)
     }
     return 0;
 }
+#endif
 
 static int validate_codec_tag(AVFormatContext *s, AVStream *st)
 {
@@ -2789,15 +2791,29 @@ static int validate_codec_tag(AVFormatContext *s, AVStream *st)
     return 1;
 }
 
+#if FF_API_FORMAT_PARAMETERS
 int av_write_header(AVFormatContext *s)
 {
-    int ret, i;
+    return avformat_write_header(s, NULL);
+}
+#endif
+
+int avformat_write_header(AVFormatContext *s, AVDictionary **options)
+{
+    int ret = 0, i;
     AVStream *st;
+    AVDictionary *tmp = NULL;
+
+    if (options)
+        av_dict_copy(&tmp, *options, 0);
+    if ((ret = av_opt_set_dict(s, &tmp)) < 0)
+        goto fail;
 
     // some sanity checks
     if (s->nb_streams == 0 && !(s->oformat->flags & AVFMT_NOSTREAMS)) {
         av_log(s, AV_LOG_ERROR, "no streams\n");
-        return AVERROR(EINVAL);
+        ret = AVERROR(EINVAL);
+        goto fail;
     }
 
     for(i=0;i<s->nb_streams;i++) {
@@ -2807,7 +2823,8 @@ int av_write_header(AVFormatContext *s)
         case AVMEDIA_TYPE_AUDIO:
             if(st->codec->sample_rate<=0){
                 av_log(s, AV_LOG_ERROR, "sample rate not set\n");
-                return AVERROR(EINVAL);
+                ret = AVERROR(EINVAL);
+                goto fail;
             }
             if(!st->codec->block_align)
                 st->codec->block_align = st->codec->channels *
@@ -2816,15 +2833,18 @@ int av_write_header(AVFormatContext *s)
         case AVMEDIA_TYPE_VIDEO:
             if(st->codec->time_base.num<=0 || st->codec->time_base.den<=0){ //FIXME audio too?
                 av_log(s, AV_LOG_ERROR, "time base not set\n");
-                return AVERROR(EINVAL);
+                ret = AVERROR(EINVAL);
+                goto fail;
             }
             if((st->codec->width<=0 || st->codec->height<=0) && !(s->oformat->flags & AVFMT_NODIMENSIONS)){
                 av_log(s, AV_LOG_ERROR, "dimensions not set\n");
-                return AVERROR(EINVAL);
+                ret = AVERROR(EINVAL);
+                goto fail;
             }
             if(av_cmp_q(st->sample_aspect_ratio, st->codec->sample_aspect_ratio)){
                 av_log(s, AV_LOG_ERROR, "Aspect ratio mismatch between encoder and muxer layer\n");
-                return AVERROR(EINVAL);
+                ret = AVERROR(EINVAL);
+                goto fail;
             }
             break;
         }
@@ -2841,7 +2861,8 @@ int av_write_header(AVFormatContext *s)
                     av_log(s, AV_LOG_ERROR,
                            "Tag %s/0x%08x incompatible with output codec id '%d'\n",
                            tagbuf, st->codec->codec_tag, st->codec->codec_id);
-                    return AVERROR_INVALIDDATA;
+                    ret = AVERROR_INVALIDDATA;
+                    goto fail;
                 }
             }else
                 st->codec->codec_tag= av_codec_get_tag(s->oformat->codec_tag, st->codec->codec_id);
@@ -2854,8 +2875,16 @@ int av_write_header(AVFormatContext *s)
 
     if (!s->priv_data && s->oformat->priv_data_size > 0) {
         s->priv_data = av_mallocz(s->oformat->priv_data_size);
-        if (!s->priv_data)
-            return AVERROR(ENOMEM);
+        if (!s->priv_data) {
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+        if (s->oformat->priv_class) {
+            *(const AVClass**)s->priv_data= s->oformat->priv_class;
+            av_opt_set_defaults(s->priv_data);
+            if ((ret = av_opt_set_dict(s->priv_data, &tmp)) < 0)
+                goto fail;
+        }
     }
 
     /* set muxer identification string */
@@ -2866,7 +2895,7 @@ int av_write_header(AVFormatContext *s)
     if(s->oformat->write_header){
         ret = s->oformat->write_header(s);
         if (ret < 0)
-            return ret;
+            goto fail;
     }
 
     /* init PTS generation */
@@ -2885,12 +2914,22 @@ int av_write_header(AVFormatContext *s)
             break;
         }
         if (den != AV_NOPTS_VALUE) {
-            if (den <= 0)
-                return AVERROR_INVALIDDATA;
+            if (den <= 0) {
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
             av_frac_init(&st->pts, 0, 0, den);
         }
     }
+
+    if (options) {
+        av_dict_free(options);
+        *options = tmp;
+    }
     return 0;
+fail:
+    av_dict_free(&tmp);
+    return ret;
 }
 
 //FIXME merge with compute_pkt_fields