lavf/ffmenc: store recommended encoder configuration

ffmenc will store recommended encoder configuration if present.
This will allow the user to base on local defaults and
apply only explicitly set options.

If recommended encoder configuration is not present, then
non-default context's options are stored.

Signed-off-by: Lukasz Marek <lukasz.m.luki2@gmail.com>

libavformat/ffmenc.c

@@ -162,6 +162,60 @@ static int ffm_write_header_codec_ctx(AVIOContext *pb, AVCodecContext *ctx, unsi
 #undef ENC
 }
 
+static int ffm_write_recommended_config(AVIOContext *pb, AVCodecContext *ctx, unsigned tag,
+                                        const char *configuration)
+{
+    int ret;
+    const AVCodec *enc = ctx->codec ? ctx->codec : avcodec_find_encoder(ctx->codec_id);
+    AVIOContext *tmp;
+    AVDictionaryEntry *t = NULL;
+    AVDictionary *all = NULL, *comm = NULL, *prv = NULL;
+    char *buf = NULL;
+
+    if (!enc || !enc->priv_class || !enc->priv_data_size) {
+        /* codec is not known/has no private options, so save everything as common options */
+        if (avio_open_dyn_buf(&tmp) < 0)
+            return AVERROR(ENOMEM);
+        avio_put_str(tmp, configuration);
+        write_header_chunk(pb, tmp, tag);
+        return 0;
+    }
+
+    if ((ret = av_dict_parse_string(&all, configuration, "=", ",", 0)) < 0)
+        return ret;
+
+    while ((t = av_dict_get(all, "", t, AV_DICT_IGNORE_SUFFIX))) {
+        if (av_opt_find((void *)&enc->priv_class, t->key, NULL, 0, AV_OPT_SEARCH_FAKE_OBJ)) {
+            if ((ret = av_dict_set(&prv, t->key, t->value, 0)) < 0)
+                goto fail;
+        } else if ((ret = av_dict_set(&comm, t->key, t->value, 0)) < 0)
+            goto fail;
+    }
+
+    if (comm) {
+        if ((ret = av_dict_get_string(comm, &buf, '=', ',')) < 0 ||
+            (ret = avio_open_dyn_buf(&tmp)) < 0)
+            goto fail;
+        avio_put_str(tmp, buf);
+        av_freep(&buf);
+        write_header_chunk(pb, tmp, tag);
+    }
+    if (prv) {
+        if ((ret = av_dict_get_string(prv, &buf, '=', ',')) < 0 ||
+            (ret = avio_open_dyn_buf(&tmp)) < 0)
+            goto fail;
+        avio_put_str(tmp, buf);
+        write_header_chunk(pb, tmp, MKBETAG('C', 'P', 'R', 'V'));
+    }
+
+  fail:
+    av_free(buf);
+    av_dict_free(&all);
+    av_dict_free(&comm);
+    av_dict_free(&prv);
+    return ret;
+}
+
 static int ffm_write_header(AVFormatContext *s)
 {
     FFMContext *ffm = s->priv_data;
@@ -220,12 +274,24 @@ static int ffm_write_header(AVFormatContext *s)
         /* specific info */
         switch(codec->codec_type) {
         case AVMEDIA_TYPE_VIDEO:
-            if ((ret = ffm_write_header_codec_ctx(s->pb, codec, MKBETAG('S', '2', 'V', 'I'), AV_OPT_FLAG_VIDEO_PARAM)) < 0 ||
+            if (st->recommended_encoder_configuration) {
+                av_log(NULL, AV_LOG_DEBUG, "writing recommended configuration: %s\n",
+                       st->recommended_encoder_configuration);
+                if ((ret = ffm_write_recommended_config(s->pb, codec, MKBETAG('S', '2', 'V', 'I'),
+                                                        st->recommended_encoder_configuration)) < 0)
+                return ret;
+            } else if ((ret = ffm_write_header_codec_ctx(s->pb, codec, MKBETAG('S', '2', 'V', 'I'), AV_OPT_FLAG_VIDEO_PARAM)) < 0 ||
                        (ret = ffm_write_header_codec_private_ctx(s->pb, codec, AV_OPT_FLAG_VIDEO_PARAM)) < 0)
                 return ret;
             break;
         case AVMEDIA_TYPE_AUDIO:
-            if ((ret = ffm_write_header_codec_ctx(s->pb, codec, MKBETAG('S', '2', 'A', 'U'), AV_OPT_FLAG_AUDIO_PARAM)) < 0 ||
+            if (st->recommended_encoder_configuration) {
+                av_log(NULL, AV_LOG_DEBUG, "writing recommended configuration: %s\n",
+                       st->recommended_encoder_configuration);
+                if ((ret = ffm_write_recommended_config(s->pb, codec, MKBETAG('S', '2', 'A', 'U'),
+                                                        st->recommended_encoder_configuration)) < 0)
+                return ret;
+            } else if ((ret = ffm_write_header_codec_ctx(s->pb, codec, MKBETAG('S', '2', 'A', 'U'), AV_OPT_FLAG_AUDIO_PARAM)) < 0 ||
                      (ret = ffm_write_header_codec_private_ctx(s->pb, codec, AV_OPT_FLAG_AUDIO_PARAM)) < 0)
                 return ret;
             break;

libavformat/version.h

@@ -31,7 +31,7 @@
 
 #define LIBAVFORMAT_VERSION_MAJOR 56
 #define LIBAVFORMAT_VERSION_MINOR  15
-#define LIBAVFORMAT_VERSION_MICRO 100
+#define LIBAVFORMAT_VERSION_MICRO 101
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \