我有一些 vob 文件，想将它们连接起来并写入 mkv。我最初尝试过：
ffmpeg -i "concat:VTS_02_1.VOB|VTS_02_2.VOB|VTS_02_3.VOB|VTS_02_4.VOB|VTS_02_5.VOB" -vf scale=1920x1080:flags=lanczos -c:v libx264 -preset slow -crf 21 -c:a copy output.mkv
但这根本没有复制音频：
ffmpeg version N-89977-gddd851f7cb-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 6.4.0 (Debian 6.4.0-11) 20171206
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-6 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gray --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzimg
libavutil 56. 7.100 / 56. 7.100
libavcodec 58. 10.100 / 58. 10.100
libavformat 58. 9.100 / 58. 9.100
libavdevice 58. 1.100 / 58. 1.100
libavfilter 7. 11.101 / 7. 11.101
libswscale 5. 0.101 / 5. 0.101
libswresample 3. 0.101 / 3. 0.101
libpostproc 55. 0.100 / 55. 0.100
[mpeg @ 0x54fcb80] Could not find codec parameters for stream 2 (Audio: ac3, 0 channels): unspecified sample format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, mpeg, from 'concat:VTS_02_1.VOB|VTS_02_2.VOB|VTS_02_3.VOB|VTS_02_4.VOB|VTS_02_5.VOB':
Duration: 02:30:25.48, start: 0.233567, bitrate: 3950 kb/s
Stream #0:0[0x1bf]: Data: dvd_nav_packet
Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, top first), 720x480 [SAR 32:27 DAR 16:9], 29.97 fps, 59.94 tbr, 90k tbn, 59.94 tbc
Stream #0:2[0x80]: Audio: ac3, 0 channels
Stream mapping:
Stream #0:1 -> #0:0 (mpeg2video (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 0x5586ec0] using SAR=1/1
[libx264 @ 0x5586ec0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x5586ec0] profile High, level 5.0
[libx264 @ 0x5586ec0] 264 - core 155 r69 7d0ff22 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=5 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=8 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=2 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=50 rc=crf mbtree=1 crf=21.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, matroska, to 'output.mkv':
Metadata:
encoder : Lavf58.9.100
Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 29.97 fps, 1k tbn, 29.97 tbc
Metadata:
encoder : Lavc58.10.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
因此我明确地映射了流：
ffmpeg -i "concat:VTS_02_1.VOB|VTS_02_2.VOB|VTS_02_3.VOB|VTS_02_4.VOB|VTS_02_5.VOB" -vf scale=1920x1080:flags=lanczos -c:v libx264 -preset slow -crf 21 -c:a copy -map 0:1 -map 0:2 output.mkv
但这次它说采样率未设置：
built with gcc 6.4.0 (Debian 6.4.0-11) 20171206
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-6 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gray --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzimg
libavutil 56. 7.100 / 56. 7.100
libavcodec 58. 10.100 / 58. 10.100
libavformat 58. 9.100 / 58. 9.100
libavdevice 58. 1.100 / 58. 1.100
libavfilter 7. 11.101 / 7. 11.101
libswscale 5. 0.101 / 5. 0.101
libswresample 3. 0.101 / 3. 0.101
libpostproc 55. 0.100 / 55. 0.100
[mpeg @ 0x5ae7b80] Could not find codec parameters for stream 2 (Audio: ac3, 0 channels): unspecified sample format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, mpeg, from 'concat:VTS_02_1.VOB|VTS_02_2.VOB|VTS_02_3.VOB|VTS_02_4.VOB|VTS_02_5.VOB':
Duration: 02:30:25.48, start: 0.233567, bitrate: 3950 kb/s
Stream #0:0[0x1bf]: Data: dvd_nav_packet
Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, top first), 720x480 [SAR 32:27 DAR 16:9], 29.97 fps, 59.94 tbr, 90k tbn, 59.94 tbc
Stream #0:2[0x80]: Audio: ac3, 0 channels
File 'output.mkv' already exists. Overwrite ? [y/N] y
Stream mapping:
Stream #0:1 -> #0:0 (mpeg2video (native) -> h264 (libx264))
Stream #0:2 -> #0:1 (copy)
Press [q] to stop, [?] for help
[libx264 @ 0x5af1800] using SAR=1/1
[libx264 @ 0x5af1800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x5af1800] profile High, level 5.0
[libx264 @ 0x5af1800] 264 - core 155 r69 7d0ff22 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=5 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=8 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=2 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=50 rc=crf mbtree=1 crf=21.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[mp4 @ 0x5af0980] sample rate not set
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Error initializing output stream 0:0 --
Conversion failed!
答案1
正如日志所述，设置较高的分析持续时间和探测大小值。
ffmpeg -analyzeduration 100M -probesize 100M -i "concat:VTS_02_1.VOB|VTS_02_2.VOB|VTS_02_3.VOB|VTS_02_4.VOB|VTS_02_5.VOB" -vf scale=1920x1080:flags=lanczos -c:v libx264 -preset slow -crf 21 -c:a copy output.mkv