libff: Add override for codec compatability check

In some cases the result of the compatability check is wrong.
For example the format "mpegts" only shows "mpeg2video" as an
encoder even though other codecs such as h.264 are supported by
ffmpeg's muxer for that container and are used within that container
in some applications.

Closes jp9000/obs-studio#804

deps/libff/libff/ff-util.c

@@ -99,7 +99,8 @@ static const AVCodec *next_codec_for_id(enum AVCodecID id, const AVCodec *prev)
 
 static void add_codec_to_list(const struct ff_format_desc *format_desc,
 		struct ff_codec_desc **first, struct ff_codec_desc **current,
-		enum AVCodecID id, const AVCodec *codec)
+		enum AVCodecID id, const AVCodec *codec,
+		bool ignore_compatability)
 {
 	if (codec == NULL)
 		codec = avcodec_find_encoder(id);
@@ -112,11 +113,13 @@ static void add_codec_to_list(const struct ff_format_desc *format_desc,
 	if (!av_codec_is_encoder(codec))
 		return;
 
-	// Format doesn't support this codec
-	unsigned int tag = av_codec_get_tag(format_desc->codec_tags,
-			codec->id);
-	if (tag == 0)
-		return;
+	if (!ignore_compatability) {
+		// Format doesn't support this codec
+		unsigned int tag = av_codec_get_tag(format_desc->codec_tags,
+				codec->id);
+		if (tag == 0)
+			return;
+	}
 
 	struct ff_codec_desc *d = av_mallocz(sizeof(struct ff_codec_desc));
 
@@ -150,16 +153,17 @@ static void add_codec_to_list(const struct ff_format_desc *format_desc,
 
 static void get_codecs_for_id(const struct ff_format_desc *format_desc,
 		struct ff_codec_desc **first, struct ff_codec_desc **current,
-		enum AVCodecID id)
+		enum AVCodecID id, bool ignore_compatability)
 {
 	const AVCodec *codec = NULL;
 	while ((codec = next_codec_for_id(id, codec)))
 		add_codec_to_list(format_desc, first, current, codec->id,
-				codec);
+				codec, ignore_compatability);
 }
 
 const struct ff_codec_desc *ff_codec_supported(
-		const struct ff_format_desc *format_desc)
+		const struct ff_format_desc *format_desc,
+		bool ignore_compatability)
 {
 	const AVCodecDescriptor **codecs;
 	unsigned int size;
@@ -172,7 +176,8 @@ const struct ff_codec_desc *ff_codec_supported(
 
 	for(i = 0; i < size; i++) {
 		const AVCodecDescriptor *codec = codecs[i];
-		get_codecs_for_id(format_desc, &first, &current, codec->id);
+		get_codecs_for_id(format_desc, &first, &current, codec->id,
+				ignore_compatability);
 	}
 
 	av_free((void *)codecs);

deps/libff/libff/ff-util.h

@@ -37,7 +37,8 @@ const char *ff_codec_name_from_id(int codec_id);
 
 // Codec Description
 const struct ff_codec_desc *ff_codec_supported(
-		const struct ff_format_desc *format_desc);
+		const struct ff_format_desc *format_desc,
+		bool ignore_compatability);
 void ff_codec_desc_free(const struct ff_codec_desc *codec_desc);
 const char *ff_codec_desc_name(const struct ff_codec_desc *codec_desc);
 const char *ff_codec_desc_long_name(const struct ff_codec_desc *codec_desc);