[FFmpeg-devel] [PATCH 2/3] lavf/ffmenc: store recommended encoder configuration

[Lukasz Marek]

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 at gmail.com>
---
 libavformat/ffmenc.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 70 insertions(+), 4 deletions(-)

diff --git a/libavformat/ffmenc.c b/libavformat/ffmenc.c
index c64c26b..e6d1a31 100644
--- a/libavformat/ffmenc.c
+++ b/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;
@@ -220,13 +274,25 @@ 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 ||
-                (ret = ffm_write_header_codec_private_ctx(s->pb, codec, 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 ||
-                (ret = ffm_write_header_codec_private_ctx(s->pb, codec, 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;
         default:
-- 
1.9.1