我开发了一个视频会议应用程序，可以单独记录视频流，现在我正在寻找一种合并它们的方法。目前，我正在尝试-itsoffset和hstack使用以下命令并排堆叠2个视频：
ffmpeg \
-itsoffset 17 -i smaller.mp4 \
-itsoffset 0 -i bigger.mp4 \
-filter_complex hstack=inputs=2 \
-c:v libx264 -crf 23 out.mp4
结果是一个并排视频，两个流保持冻结状态达17秒，然后开始播放，甚至更大的.mp4视频也应该在时间0开始播放。
任何帮助将不胜感激！
ffmpeg详细：
ffmpeg version 4.1 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 4.9.2 (Debian 4.9.2-10+deb8u1)
configuration: --enable-gpl --enable-postproc --enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-libx264 --enable-libspeex --enab le-shared --enable-pthreads --enable-libopenjpeg --enable-nonfree --enable-libopus --enable-libvorbis --enable-libvpx
libavutil 56. 22.100 / 56. 22.100
libavcodec 58. 35.100 / 58. 35.100
libavformat 58. 20.100 / 58. 20.100
libavdevice 58. 5.100 / 58. 5.100
libavfilter 7. 40.101 / 7. 40.101
libswscale 5. 3.100 / 5. 3.100
libswresample 3. 3.100 / 3. 3.100
libpostproc 55. 3.100 / 55. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'smaller.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.20.100
Duration: 00:00:05.16, start: 0.000000, bitrate: 444 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 330 kb/s, 32 fps, 32 tbr, 16384 tbn, 64 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 103 kb/s (default)
Metadata:
handler_name : SoundHandler
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'bigger.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf56.36.100
Duration: 00:00:22.03, start: 0.000000, bitrate: 290 kb/s
Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 480x360 [SAR 1:1 DAR 4:3], 177 kb/s, 32 fps, 32 tbr, 16384 tbn, 64 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 103 kb/s (default)
Metadata:
handler_name : SoundHandler
File 'out.mp4' already exists. Overwrite ? [y/N] y
Stream mapping:
Stream #0:0 (h264) -> hstack:input0 (graph 0)
Stream #1:0 (h264) -> hstack:input1 (graph 0)
hstack (graph 0) -> Stream #0:0 (libx264)
Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x206ed00] using SAR=1/1
[libx264 @ 0x206ed00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x206ed00] profile High, level 3.1
[libx264 @ 0x206ed00] 264 - core 146 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - 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=3 lookahead_threads=1 sliced_thre ads=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=25 scene cut=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 'out.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.20.100
Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 960x360 [SAR 1:1 DAR 8:3], q=-1--1, 32 fps, 16384 tbn, 32 tbc (default)
Metadata:
encoder : Lavc58.35.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
encoder : Lavc58.35.100 aac
frame= 709 fps=130 q=-1.0 Lsize= 573kB time=00:00:22.12 bitrate= 212.2kbits/s dup=544 drop=0 speed=4.05x
video:478kB audio:81kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.445685%
[libx264 @ 0x206ed00] frame I:3 Avg QP:16.86 size: 38355
[libx264 @ 0x206ed00] frame P:190 Avg QP:18.22 size: 1633
[libx264 @ 0x206ed00] frame B:516 Avg QP:16.23 size: 123
[libx264 @ 0x206ed00] consecutive B-frames: 1.3% 2.8% 6.8% 89.1%
[libx264 @ 0x206ed00] mb I I16..4: 6.6% 54.8% 38.6%
[libx264 @ 0x206ed00] mb P I16..4: 0.4% 1.5% 0.2% P16..4: 8.7% 4.0% 1.9% 0.0% 0.0% skip:83.3%
[libx264 @ 0x206ed00] mb B I16..4: 0.0% 0.1% 0.0% B16..8: 4.2% 0.3% 0.0% direct: 0.0% skip:95.4% L0:37.2% L1:58.9% BI: 4.0%
[libx264 @ 0x206ed00] 8x8 transform intra:66.2% inter:63.4%
[libx264 @ 0x206ed00] coded y,uvDC,uvAC intra: 66.1% 65.6% 21.6% inter: 1.7% 1.1% 0.0%
[libx264 @ 0x206ed00] i16 v,h,dc,p: 21% 26% 11% 42%
[libx264 @ 0x206ed00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 23% 13% 5% 7% 8% 7% 7% 6%
[libx264 @ 0x206ed00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 28% 24% 9% 6% 7% 7% 6% 7% 7%
[libx264 @ 0x206ed00] i8c dc,h,v,p: 46% 25% 20% 9%
[libx264 @ 0x206ed00] Weighted P-Frames: Y:1.1% UV:0.0%
[libx264 @ 0x206ed00] ref P L0: 66.0% 19.4% 12.0% 2.6% 0.0%
[libx264 @ 0x206ed00] ref B L0: 87.2% 11.8% 1.0%
[libx264 @ 0x206ed00] ref B L1: 95.2% 4.8%
[libx264 @ 0x206ed00] kb/s:176.52
[aac @ 0x204aa00] Qavg: 247.398
答案 0 :(得分：0)
hstack不按时间戳同步。您需要填充延迟的视频。
ffmpeg \
-i smaller.mp4 \
-i bigger.mp4 \
-filter_complex \
"[0]tpad=start_duration=17[left];\
[left][1]hstack=inputs=2;\
[0]adelay=17s|17s[lefta];[lefta][1]amix=2" \
-c:v libx264 -crf 23 out.mp4