mkv该轨道信息：
Stream #0:2(jpn): Subtitle: hdmv_pgs_subtitle (default)
抽取命令：
（简化）
ffmpeg.exe -i "input.mkv" -map 0:2 "output.sup"
（原命令）
ffmpeg.exe -i "E:\Fate_EXTRA_Last Encore\[UCCUSS] Fate／EXTRA Last Encore 第01話 「今は旧き辺獄の底 ―プレテリトゥス・リンブス・ヴォラーゴ―」 (BD 1920x1080p AVC FLAC SUP).mkv" -map 0:2 "E:\Fate_EXTRA_Last Encore\[UCCUSS] Fate／EXTRA Last Encore 第01話 「今は旧き辺獄の底 ―プレテリトゥス・リンブス・ヴォラーゴ―」 (BD 1920x1080p AVC FLAC SUP).jpn.sup" -y
运行结果：
ffmpeg version N-93044-g2e2b44baba Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 8.2.1 (GCC) 20181201
configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
libavutil 56. 26.100 / 56. 26.100
libavcodec 58. 46.100 / 58. 46.100
libavformat 58. 26.100 / 58. 26.100
libavdevice 58. 6.101 / 58. 6.101
libavfilter 7. 48.100 / 7. 48.100
libswscale 5. 4.100 / 5. 4.100
libswresample 3. 4.100 / 3. 4.100
libpostproc 55. 4.100 / 55. 4.100
[matroska,webm @ 0000013c2e24b0c0] Could not find codec parameters for stream 2 (Subtitle: hdmv_pgs_subtitle (pgssub)): unspecified size
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, matroska,webm, from 'E:\Fate_EXTRA_Last Encore\[UCCUSS] Fate／EXTRA Last Encore 第01話 「今は旧き辺獄の底 ―プレテリトゥス・リンブス・ヴォラーゴ―」 (BD 1920x1080p AVC FLAC SUP).mkv':
Metadata:
encoder : libebml v1.3.3 + libmatroska v1.4.4
creation_time : 2018-08-16T12:47:21.000000Z
Duration: 00:25:12.06, start: 0.000000, bitrate: 17624 kb/s
Stream #0:0: Video: h264 (High), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
Stream #0:1(jpn): Audio: flac, 48000 Hz, stereo, s32 (24 bit) (default)
Stream #0:2(jpn): Subtitle: hdmv_pgs_subtitle (default)
Automatic encoder selection failed for output stream #0:0. Default encoder for format sup (codec hdmv_pgs_subtitle) is probably disabled. Please choose an encoder manually.
Error selecting an encoder for stream 0:0
没有文件生成
请问encoder咋设置！在线等！急！