我可以成功地将几个视频合并成一个（使用这方法）中间带有不错的淡入淡出效果，但输出视频不包含音频。我正在使用命令-filter_complex。
我已经设法修改了命令，以便音频也可以出现，但我一直得到缓冲区队列溢出、丢弃解码时出错。奇怪的是，音频流正确合并，中间有淡入淡出效果，而视频流由于丢帧而仅包含原始输入的几个百分点。这是我使用的命令：
ffmpeg -i 0.mp4 -i 1.mp4 -i 2.mp4 -i 3.mp4 -f lavfi -i color=white:s=1920x1080
-filter_complex
"
[0:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=28:d=1:alpha=1,setpts=PTS-STARTPTS[v0];
[1:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=98:d=1:alpha=1,setpts=PTS-STARTPTS+28/TB[v1];
[2:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=101:d=1:alpha=1,setpts=PTS-STARTPTS+126/TB[v2];
[3:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=37:d=1:alpha=1,setpts=PTS-STARTPTS+227/TB[v3];
[4:v]trim=duration=265[over0];
[0:a]afade=in:st=0:d=1,afade=out:st=28:d=1[a0];
[1:a]afade=in:st=0:d=1,afade=out:st=98:d=1,adelay=28000[a1];
[2:a]afade=in:st=0:d=1,afade=out:st=101:d=1,adelay=126000[a2];
[3:a]afade=in:st=0:d=1,afade=out:st=37:d=1,adelay=227000[a3];
[a0][a1][a2][a3]amix=inputs=4,volume=2;
[over0][v0]overlay[over1];
[over1][v1]overlay[over2];
[over2][v2]overlay[over3];
[over3][v3]overlay=format=yuv420[output]
"
-vcodec libx264 -map [output] output.mp4
此命令产生无法使用的输出，丢失了 90% 以上的帧。音频命令似乎是问题所在，因为当我删除它们时，视频可以正确合并，不会丢失任何帧：
ffmpeg -i 0.mp4 -i 1.mp4 -i 2.mp4 -i 3.mp4 -f lavfi -i color=white:s=1920x1080
-filter_complex
"
[0:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=28:d=1:alpha=1,setpts=PTS-STARTPTS[v0];
[1:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=98:d=1:alpha=1,setpts=PTS-STARTPTS+28/TB[v1];
[2:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=101:d=1:alpha=1,setpts=PTS-STARTPTS+126/TB[v2];
[3:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=37:d=1:alpha=1,setpts=PTS-STARTPTS+227/TB[v3];
[4:v]trim=duration=265[over0];
[over0][v0]overlay[over1];
[over1][v1]overlay[over2];
[over2][v2]overlay[over3];
[over3][v3]overlay=format=yuv420[output]
"
-vcodec libx264 -map [output] output.mp4
上述命令的输出不包含音频，但包含所有视频帧。
我尝试使用其他命令来连接音频流，但amix似乎只有这个命令在这里有效。我花了好几个小时试图解决这个问题，但还是没能解决。我是不是漏掉了什么，还是我做错了？欢迎提出任何建议...
另外，这是完整的控制台输出（我只删除了一些元数据）。在收到一堆“缓冲区队列溢出”错误后，我退出了编码，否则输出会比这大得多：
>ffmpeg -i 0.mp4 -i 1.mp4 -i 2.mp4 -i 3.mp4 -f lavfi -i color=white:s=1920x1080 -filter_complex "[0:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=28:d=1:alpha
=1,setpts=PTS-STARTPTS[v0];[1:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=98:d=1:alpha=1,setpts=PTS-STARTPTS+28/TB[v1];[2:v]format=pix_fmts=yuva420p,fade=t=
in:st=0:d=1:alpha=1,fade=t=out:st=101:d=1:alpha=1,setpts=PTS-STARTPTS+126/TB[v2];[3:v]format=pix_fmts=yuva420p,fade=t=in:st=0:d=1:alpha=1,fade=t=out:st=37:d=1:alpha=1,setpts=PTS-ST
ARTPTS+227/TB[v3];[4:v]trim=duration=265[over0];[0:a]afade=in:st=0:d=1,afade=out:st=28:d=1[a0];[1:a]afade=in:st=0:d=1,afade=out:st=98:d=1,adelay=28000[a1];[2:a]afade=in:st=0:d=1,af
ade=out:st=101:d=1,adelay=126000[a2];[3:a]afade=in:st=0:d=1,afade=out:st=37:d=1,adelay=227000[a3];[a0][a1][a2][a3]amix=inputs=4,volume=2;[over0][v0]overlay[over1];[over1][v1]overla
y[over2];[over2][v2]overlay[over3];[over3][v3]overlay=format=yuv420[output]" -vcodec libx264 -map [output] output.mp4
ffmpeg version N-71959-g9253cc4 Copyright (c) 2000-2015 the FFmpeg developers
built with gcc 4.9.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-li
bass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libm
p3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --en
able-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enabl
e-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
libavutil 54. 23.101 / 54. 23.101
libavcodec 56. 37.102 / 56. 37.102
libavformat 56. 32.100 / 56. 32.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '0.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
Duration: 00:00:29.31, start: 0.000000, bitrate: 19944 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 19831 kb/s, 29.81 fps, 30 tbr, 30k tbn, 60k tbc (default)
Metadata:
handler_name : VideoHandler
encoder : AVC Coding
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 97 kb/s (default)
Metadata:
handler_name : SoundHandler
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
creation_time : 2015-03-24 19:06:46
date : 2015-03-24T19:08:28Z
date-eng : 2015-03-24T19:08:28Z
location : █████████████████
location-eng : █████████████████
Duration: 00:01:39.75, start: 0.000000, bitrate: 20017 kb/s
Stream #1:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 19953 kb/s, 30 fps, 30 tbr, 30k tbn, 60k tbc (default)
Metadata:
creation_time : 2015-03-24 19:06:46
handler_name : VideoHandler
encoder : AVC Coding
Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 98 kb/s (default)
Metadata:
creation_time : 2015-03-24 19:06:46
handler_name : SoundHandler
Input #2, mov,mp4,m4a,3gp,3g2,mj2, from '2.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
creation_time : 2015-04-21 15:56:27
date : 2015-04-21T15:58:12Z
date-eng : 2015-04-21T15:58:12Z
location : █████████████████
location-eng : █████████████████
Duration: 00:01:42.35, start: 0.000000, bitrate: 20020 kb/s
Stream #2:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 19948 kb/s, 29.99 fps, 30 tbr, 30k tbn, 60k tbc (default)
Metadata:
creation_time : 2015-04-21 15:56:27
handler_name : VideoHandler
encoder : AVC Coding
Stream #2:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 97 kb/s (default)
Metadata:
creation_time : 2015-04-21 15:56:27
handler_name : SoundHandler
Input #3, mov,mp4,m4a,3gp,3g2,mj2, from '3.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
creation_time : 2015-05-02 12:20:47
date : 2015-05-02T12:21:28Z
date-eng : 2015-05-02T12:21:28Z
location : █████████████████
location-eng : █████████████████
Duration: 00:00:38.89, start: 0.000000, bitrate: 19937 kb/s
Stream #3:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 19934 kb/s, 29.98 fps, 30 tbr, 30k tbn, 60k tbc (default)
Metadata:
creation_time : 2015-05-02 12:20:47
handler_name : VideoHandler
encoder : AVC Coding
Stream #3:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 97 kb/s (default)
Metadata:
creation_time : 2015-05-02 12:20:47
handler_name : SoundHandler
Input #4, lavfi, from 'color=white:s=1920x1080':
Duration: N/A, start: 0.000000, bitrate: N/A
Stream #4:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
[libx264 @ 0000000004fa0020] using SAR=1/1
[libx264 @ 0000000004fa0020] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.1 Cache64
[libx264 @ 0000000004fa0020] profile High, level 4.0
[libx264 @ 0000000004fa0020] 264 - core 146 r2538 121396c - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 a
nalyse=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=3 lookah
ead_threads=1 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 key
int=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'output.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp41isom
encoder : Lavf56.32.100
Stream #0:0: Audio: aac (libvo_aacenc) ([64][0][0][0] / 0x0040), 44100 Hz, mono, s16, 128 kb/s (default)
Metadata:
encoder : Lavc56.37.102 libvo_aacenc
Stream #0:1: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
Metadata:
encoder : Lavc56.37.102 libx264
Stream mapping:
Stream #0:0 (h264) -> format
Stream #0:1 (aac) -> afade
Stream #1:0 (h264) -> format
Stream #1:1 (aac) -> afade
Stream #2:0 (h264) -> format
Stream #2:1 (aac) -> afade
Stream #3:0 (h264) -> format
Stream #3:1 (aac) -> afade
Stream #4:0 (rawvideo) -> trim
volume -> Stream #0:0 (libvo_aacenc)
overlay -> Stream #0:1 (libx264)
Press [q] to stop, [?] for help
[Parsed_overlay_31 @ 0000000004fc3bc0] [framesync @ 0000000005173a68] Buffer queue overflow, dropping.
Last message repeated 3 times
[Parsed_overlay_31 @ 0000000004fc3bc0] [framesync @ 0000000005173a68] Buffer queue overflow, dropping.
Last message repeated 2 times
[Parsed_overlay_32 @ 0000000004fc47c0] [framesync @ 000000000517d388] Buffer queue overflow, dropping.
Last message repeated 7 times
[Parsed_overlay_33 @ 0000000004fc3680] [framesync @ 000000000517d988] Buffer queue overflow, dropping.
Last message repeated 6 times
[Parsed_overlay_31 @ 0000000004fc3bc0] [framesync @ 0000000005173a68] Buffer queue overflow, dropping.
Last message repeated 9 times
[Parsed_overlay_33 @ 0000000004fc3680] [framesync @ 000000000517d988] Buffer queue overflow, dropping.
Last message repeated 9 times
[Parsed_overlay_32 @ 0000000004fc47c0] [framesync @ 000000000517d388] Buffer queue overflow, dropping.
Last message repeated 9 times
[Parsed_overlay_31 @ 0000000004fc3bc0] [framesync @ 0000000005173a68] Buffer queue overflow, dropping.
[Parsed_overlay_32 @ 0000000004fc47c0] [framesync @ 000000000517d388] Buffer queue overflow, dropping.
[Parsed_overlay_33 @ 0000000004fc3680] [framesync @ 000000000517d988] Buffer queue overflow, dropping.
frame= 75 fps=3.6 q=-1.0 Lsize= 2425kB time=00:00:02.97 bitrate=6681.4kbits/s
video:2374kB audio:46kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.183280%
[libx264 @ 0000000004fa0020] frame I:5 Avg QP:18.75 size: 45143
[libx264 @ 0000000004fa0020] frame P:50 Avg QP:24.25 size: 36116
[libx264 @ 0000000004fa0020] frame B:20 Avg QP:23.56 size: 19940
[libx264 @ 0000000004fa0020] consecutive B-frames: 49.3% 45.3% 0.0% 5.3%
[libx264 @ 0000000004fa0020] mb I I16..4: 27.3% 65.2% 7.6%
[libx264 @ 0000000004fa0020] mb P I16..4: 2.8% 18.9% 1.1% P16..4: 50.6% 12.1% 3.7% 0.0% 0.0% skip:10.8%
[libx264 @ 0000000004fa0020] mb B I16..4: 0.5% 2.5% 0.1% B16..8: 42.4% 7.1% 0.6% direct: 7.0% skip:39.6% L0:55.9% L1:42.0% BI: 2.1%
[libx264 @ 0000000004fa0020] 8x8 transform intra:77.5% inter:85.8%
[libx264 @ 0000000004fa0020] coded y,uvDC,uvAC intra: 56.3% 52.7% 2.3% inter: 30.5% 46.8% 0.2%
[libx264 @ 0000000004fa0020] i16 v,h,dc,p: 46% 10% 5% 39%
[libx264 @ 0000000004fa0020] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 17% 16% 5% 10% 8% 12% 6% 7%
[libx264 @ 0000000004fa0020] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 22% 12% 5% 12% 8% 10% 4% 4%
[libx264 @ 0000000004fa0020] i8c dc,h,v,p: 61% 18% 17% 4%
[libx264 @ 0000000004fa0020] Weighted P-Frames: Y:20.0% UV:20.0%
[libx264 @ 0000000004fa0020] ref P L0: 71.4% 15.5% 9.5% 3.5% 0.0%
[libx264 @ 0000000004fa0020] ref B L0: 94.6% 5.4%
[libx264 @ 0000000004fa0020] kb/s:6480.80