From: Jan Engelhardt Edit the default codec selection such that ffmpeg -i youtube.blah.webm foobar.mkv without any further arguments can produce a result even on a reduced codec selection list. --- libavformat/matroskaenc.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) Index: ffmpeg-5.0/libavformat/matroskaenc.c =================================================================== --- ffmpeg-5.0.orig/libavformat/matroskaenc.c 2022-01-14 19:45:40.000000000 +0100 +++ ffmpeg-5.0/libavformat/matroskaenc.c 2022-02-04 08:29:14.582130919 +0100 @@ -2887,16 +2887,24 @@ static int mkv_query_codec(enum AVCodecI return 0; } +#define PREFAUDIO \ + CONFIG_LIBOPUS_ENCODER ? AV_CODEC_ID_OPUS : \ + CONFIG_AAC_ENCODER ? AV_CODEC_ID_AAC : \ + CONFIG_VORBIS_ENCODER ? AV_CODEC_ID_VORBIS : \ + AV_CODEC_ID_AC3 const AVOutputFormat ff_matroska_muxer = { .name = "matroska", .long_name = NULL_IF_CONFIG_SMALL("Matroska"), .mime_type = "video/x-matroska", .extensions = "mkv", .priv_data_size = sizeof(MatroskaMuxContext), - .audio_codec = CONFIG_LIBVORBIS_ENCODER ? - AV_CODEC_ID_VORBIS : AV_CODEC_ID_AC3, - .video_codec = CONFIG_LIBX264_ENCODER ? - AV_CODEC_ID_H264 : AV_CODEC_ID_MPEG4, + .audio_codec = PREFAUDIO, + .video_codec = + CONFIG_LIBVPX_VP9_ENCODER ? AV_CODEC_ID_VP9 : \ + CONFIG_LIBX264_ENCODER ? AV_CODEC_ID_H264 : \ + CONFIG_LIBVPX_VP8_ENCODER ? AV_CODEC_ID_VP8 : \ + CONFIG_MPEG4_ENCODER ? AV_CODEC_ID_MPEG4 : \ + AV_CODEC_ID_THEORA, .init = mkv_init, .deinit = mkv_deinit, .write_header = mkv_write_header, @@ -2954,8 +2962,7 @@ const AVOutputFormat ff_matroska_audio_m .mime_type = "audio/x-matroska", .extensions = "mka", .priv_data_size = sizeof(MatroskaMuxContext), - .audio_codec = CONFIG_LIBVORBIS_ENCODER ? - AV_CODEC_ID_VORBIS : AV_CODEC_ID_AC3, + .audio_codec = PREFAUDIO, .video_codec = AV_CODEC_ID_NONE, .init = mkv_init, .deinit = mkv_deinit,