使用 ffmpeg 将 mkv 转换为 mp4 有时会丢失视频
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【中文标题】使用 ffmpeg 将 mkv 转换为 mp4 有时会丢失视频【英文标题】：Converting mkv to mp4 with ffmpeg sometimes loses video 【发布时间】：2019-12-09 20:54:32 【问题描述】：如何创建一个尽可能通用的命令行来将 mkv 转换为 mp4？
我修复了一个问题，有时我会丢失音频（我认为），现在我正在丢失视频。
这是我目前使用的命令（我使用过一些命令，包括 -analyzeduration 1G -probesize 50M，但我总是在某些时候出现损坏的视频）：
if [[ $(pgrep -i ffmpeg) ]] ; then
echo "FFMPEG IS ALREADY RUNNING!"
else
echo "Starting mkv to mp4 conversion...";
for i in /var/www/html/uploads/Videos/*/*/*/*.mkv;
do name=$(echo "$i//.mkv/");
echo "$name";
ffmpeg -n -i "$i" -c copy -c:a aac -movflags +faststart "$name.mp4"; rm -v -f "$name.mkv";
done
fi
在我丢失图片的特定视频上运行的输出：
Starting mkv to mp4 conversion...
/var/www/html/uploads/Videos/TV/Avatar The Last Airbender/Season 1/Avatar The Last Airbender - S01E02 - The Avatar Returns WEBDL-1080p
ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 9 (GCC)
configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-***-protection -fcf-protection' --extra-ldflags='-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld ' --extra-cflags=' ' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libaom --enable-libdav1d --enable-libass --enable-libbluray --enable-libcdio --enable-libdrm --enable-libjack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libmp3lame --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzvbi --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-libmfx --enable-runtime-cpudetect
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/html/uploads/Videos/TV/Avatar The Last Airbender/Season 1/Avatar The Last Airbender - S01E02 - The Avatar Returns WEBDL-1080p.mkv':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.29.100
Duration: 00:23:59.11, start: 0.000000, bitrate: 1258 kb/s
Stream #0:0(und): Video: hevc (Main 10) (hev1 / 0x31766568), yuv420p10le(tv), 1440x1080, 1124 kb/s, SAR 1:1 DAR 4:3, 23.98 fps, 23.98 tbr, 16k tbn, 23.98 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
Output #0, mp4, to '/var/www/html/uploads/Videos/TV/Avatar The Last Airbender/Season 1/Avatar The Last Airbender - S01E02 - The Avatar Returns WEBDL-1080p.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.29.100
Stream #0:0(und): Video: hevc (Main 10) (hev1 / 0x31766568), yuv420p10le(tv), 1440x1080 [SAR 1:1 DAR 4:3], q=2-31, 1124 kb/s, 23.98 fps, 23.98 tbr, 16k tbn, 16k tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
encoder : Lavc58.54.100 aac
[mp4 @ 0x5583e9bdb8c0] Starting second pass: moving the moov atom to the beginning of the file
frame=34504 fps=1260 q=-1.0 Lsize= 221105kB time=00:23:59.08 bitrate=1258.6kbits/s speed=52.5x
video:197477kB audio:22515kB subtitle:0kB other streams:0kB global headers:2kB muxing overhead: 0.506059%
[aac @ 0x5583e9b3f140] Qavg: 562.538
编辑：
以下命令适用于上述命令没有的类似文件：
ffmpeg -n -i "$i" -c:v libx264 -c:a aac -movflags +faststart
输出：
Starting mkv to mp4 conversion...
/var/www/html/uploads/Videos/TV/Avatar The Last Airbender/Season 1/Avatar The Last Airbender - S01E03 - The Southern Air Temple WEBDL-1080p
ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 9 (GCC)
configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-***-protection -fcf-protection' --extra-ldflags='-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld ' --extra-cflags=' ' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libaom --enable-libdav1d --enable-libass --enable-libbluray --enable-libcdio --enable-libdrm --enable-libjack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libmp3lame --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzvbi --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-libmfx --enable-runtime-cpudetect
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/html/uploads/Videos/TV/Avatar The Last Airbender/Season 1/Avatar The Last Airbender - S01E03 - The Southern Air Temple WEBDL-1080p.mkv':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.29.100
Duration: 00:24:10.74, start: 0.000000, bitrate: 1354 kb/s
Stream #0:0(und): Video: hevc (Main 10) (hev1 / 0x31766568), yuv420p10le(tv), 1440x1080, 1124 kb/s, SAR 1:1 DAR 4:3, 23.98 fps, 23.98 tbr, 16k tbn, 23.98 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(eng): Audio: eac3 (ec-3 / 0x332D6365), 48000 Hz, stereo, fltp, 224 kb/s (default)
Metadata:
handler_name : SoundHandler
Side data:
audio service type: main
Stream mapping:
Stream #0:0 -> #0:0 (hevc (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (eac3 (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x563ef7ad5a40] using SAR=1/1
[libx264 @ 0x563ef7ad5a40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
[libx264 @ 0x563ef7ad5a40] profile High 10, level 4.0, 4:2:0, 10-bit
[libx264 @ 0x563ef7ad5a40] 264 - core 157 r2980 34c06d1 - H.264/MPEG-4 AVC codec - Copyleft 2003-2019 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=34 lookahead_threads=5 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=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=23 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=81 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to '/var/www/html/uploads/Videos/TV/Avatar The Last Airbender/Season 1/Avatar The Last Airbender - S01E03 - The Southern Air Temple WEBDL-1080p.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.29.100
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p10le, 1440x1080 [SAR 1:1 DAR 4:3], q=-1--1, 23.98 fps, 24k tbn, 23.98 tbc (default)
Metadata:
handler_name : VideoHandler
encoder : Lavc58.54.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
encoder : Lavc58.54.100 aac
Side data:
audio service type: main
frame= 37 fps=0.0 q=0.0 size= 0kB time=00:00:02.09 bitrate= 0.2kbits/sframe= 72 fps= 72 q=0.0 size= 0kB time=00:00:03.54 bitrate= 0.1kbits/sframe= 103 fps= 68 q=40.0 size= 0kB time=00:00:04.84 bitrate= 0.1kbits/frame= 128 fps= 64 q=40.0 size= 0kB time=00:00:05.90 bitrate= 0.1kbits/frame= 169 fps= 66 q=40.0 size= 256kB time=00:00:07.59 bitrate= 276.2kbits/frame= 194 fps= 63 q=40.0 size= 512kB time=00:00:08.66 bitrate= 484.3kbits/frame= 241 fps= 68 q=40.0 size= 512kB time=00:00:10.60 bitrate= 395.6kbits/frame= 262 fps= 64 q=40.0 size= 512kB time=00:00:11.47 bitrate= 365.5kbits/frame= 284 fps= 62 q=40.0 size= 768kB time=00:00:12.37 bitrate= 508.5kbits/frame= 312 fps= 61 q=40.0 size= 768kB time=00:00:13.54 bitrate= 464.5kbits/frame= 341 fps= 61 q=40.0 size= 1024kB time=00:00:14.74 bitrate= 569.1kbits/frame= 373 fps= 61 q=40.0 size= 1280kB time=00:00:16.10 bitrate= 651.0kbits/frame= 398 fps= 60 q=40.0 size= 1280kB time=00:00:17.13 bitrate= 612.1kbits/frame= 419 fps= 59 q=40.0 size= 1536kB time=00:00:18.02 bitrate= 698.0kbits/frame= 433 fps= 56 q=40.0 size= 1792kB time=00:00:18.60 bitrate= 789.2kbits/frame= 456 fps= 55 q=40.0 size= 2048kB time=00:00:19.56 bitrate= 857.6kbits/frame= 469 fps= 53 q=40.0 size= 2304kB time=00:00:20.11 bitrate= 938.2kbits/frame= 486 fps= 52 q=40.0 size= 2816kB time=00:00:20.82 bitrate=1108.0kbits/frame= 504 fps= 51 q=40.0 size= 3328kB time=00:00:21.58 bitrate=1262.8kbits/frame= 522 fps= 51 q=40.0 size= 4096kB time=00:00:22.31 bitrate=1503.7kbits/frame= 545 fps= 50 q=40.0 size= 4608kB time=00:00:23.27 bitrate=1621.9kbits/frame= 570 fps= 50 q=40.0 size= 5120kB time=00:00:24.34 bitrate=1723.1kbits/frame= 597 fps= 50 q=40.0 size= 5632kB time=00:00:25.45 bitrate=1812.8kbits/frame= 619 fps= 50 q=40.0 size= 5888kB time=00:00:26.38 bitrate=1827.8kbits/frame= 650 fps= 50 q=40.0 size= 6400kB time=00:00:27.66 bitrate=1894.8kbits/frame= 674 fps= 50 q=40.0 size= 6656kB time=00:00:28.65 bitrate=1903.1kbits/frame= 701 fps= 50 q=40.0 size= 6656kB time=00:00:29.78 bitrate=1830.9kbits/frame= 734 fps= 51 q=40.0 size= 6912kB time=00:00:31.12 bitrate=1819.2kbits/frame= 754 fps= 50 q=40.0 size= 7168kB time=00:00:31.97 bitrate=1836.2kbits/frame= 778 fps= 50 q=40.0 size= 7168kB time=00:00:33.00 --SNIPPED--
bitrate=1518.4kbits/frame=34775 fps= 58 q=40.0 size= 268800kB time=00:24:10.64 bitrate=1518.0kbits/[mp4 @ 0x563ef7ad45c0] Starting second pass: moving the moov atom to the beginning of the file
frame=34783 fps= 58 q=-1.0 Lsize= 269967kB time=00:24:10.68 bitrate=1524.5kbits/s speed= 2.4x
video:246310kB audio:22689kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.359968%
[libx264 @ 0x563ef7ad5a40] frame I:651 Avg QP:27.80 size: 60711
[libx264 @ 0x563ef7ad5a40] frame P:10705 Avg QP:32.02 size: 14279
[libx264 @ 0x563ef7ad5a40] frame B:23427 Avg QP:37.64 size: 2554
[libx264 @ 0x563ef7ad5a40] consecutive B-frames: 6.9% 8.1% 5.5% 79.6%
[libx264 @ 0x563ef7ad5a40] mb I I16..4: 29.6% 60.8% 9.6%
[libx264 @ 0x563ef7ad5a40] mb P I16..4: 7.7% 10.0% 1.1% P16..4: 20.4% 3.8% 2.2% 0.0% 0.0% skip:54.8%
[libx264 @ 0x563ef7ad5a40] mb B I16..4: 0.6% 0.6% 0.1% B16..8: 13.6% 1.0% 0.2% direct: 0.7% skip:83.3% L0:41.6% L1:55.3% BI: 3.1%
[libx264 @ 0x563ef7ad5a40] 8x8 transform intra:54.2% inter:75.7%
[libx264 @ 0x563ef7ad5a40] coded y,uvDC,uvAC intra: 29.1% 50.3% 11.9% inter: 3.4% 4.5% 0.1%
[libx264 @ 0x563ef7ad5a40] i16 v,h,dc,p: 25% 29% 9% 38%
[libx264 @ 0x563ef7ad5a40] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 18% 25% 4% 5% 5% 5% 5% 5%
[libx264 @ 0x563ef7ad5a40] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 14% 17% 7% 8% 9% 6% 7% 4%
[libx264 @ 0x563ef7ad5a40] i8c dc,h,v,p: 51% 22% 19% 9%
[libx264 @ 0x563ef7ad5a40] Weighted P-Frames: Y:2.7% UV:2.1%
[libx264 @ 0x563ef7ad5a40] ref P L0: 74.1% 16.9% 8.9% 0.1%
[libx264 @ 0x563ef7ad5a40] ref B L0: 85.8% 11.6% 2.6%
[libx264 @ 0x563ef7ad5a40] ref B L1: 96.8% 3.2%
[libx264 @ 0x563ef7ad5a40] kb/s:1390.85
[aac @ 0x563ef7ade100] Qavg: 572.905
removed '/var/www/html/uploads/Videos/TV/Avatar The Last Airbender/Season 1/Avatar The Last Airbender - S01E03 - The Southern Air Temple WEBDL-1080p.mkv'
Done transcoding!
【问题讨论】：
1) 您如何确认视频丢失或无法播放？日志表明视频已映射并且流复制到输出。 2）虽然输入扩展名是.mkv，但ffmpeg（可能正确）说它是MP4，所以一开始可能不需要重新复用。尝试将其重命名为 .mp4。 3) 音频已经是 AAC。建议添加检查以避免重新编码现有的 AAC。 1.为了检查，我只是在我的网站上打开视频并且只听到声音。 2. 只是重命名视频是以前丢失音频的原因，如果我在运行命令之前弄清楚如何检查 AAC，我可能会看到它以这种方式工作，但我不确定。 【参考方案1】：问题
视频正在包含在您的输出中（如 ffmpeg 日志中所示），但您的浏览器不喜欢（10 位）HEVC。
解决方案
要解决此问题，您可以重新编码为 H.264、VP9、AV1 或您的浏览器支持的其他格式。或者使用browser that supports HEVC。
您可以使用ffprobe 来确定输入的格式。音频流示例：
$ ffprobe -loglevel error -select_streams a:0 -show_entries stream=codec_name -of default=nw=1 input.mp4
codec_name=aac
如果您想在输出中去掉codec_name=，请使用-of default=nw=1:nk=1。
这将允许您在 bash 脚本中轻松使用 if/then 语句以避免不必要的重新编码。
【讨论】：
我将更新我的脚本以测试音频/视频并使用输出来决定从那里去哪里。感谢您帮助我了解出了什么问题。 @RobertW 如果您重新编码为 H.264 并且浏览器不喜欢 10 位，则将-vf format=yuv420p 添加到命令中。以上是关于使用 ffmpeg 将 mkv 转换为 mp4 有时会丢失视频的主要内容，如果未能解决你的问题，请参考以下文章