FFMPEG-几秒钟后停止流

Question

你好，亲爱的社区

这是我最近几天以来一直在处理的事情。经过在ffmpeg社区的彻底搜索，我无法找到解决方案。我无法流本地flv，到facebook rtmp服务器。

我正在运行以下命令，将我的本地flv视频流到Facebook的rtmp服务器进行现场直播--本地文件的流。

```ffmpeg -re -i SampleM.flv -acodec libmp3lame  -ar 44100 -b:a 128k -pix_fmt yuv420p -profile:v baseline -s 426x240 -bufsize 6000k -vb 400k -maxrate 1500k -deinterlace -vcodec libx264 -preset veryfast -g 30 -r 30 -f flv "rtmp://live-api.facebook.com:80/rtmp/my_key"```

It has been a misfortune-situation that even after reading `ffmpeg` documentation, I have been unable to find the issue that is leading me to this situation as follows. 

>  I am still missing something that i need to know.
>  

Following is the log to the execution of the above command.

```javascript

  built with gcc 7.3.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --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
  libavutil      56. 18.100 / 56. 18.100
  libavcodec     58. 19.101 / 58. 19.101
  libavformat    58. 13.102 / 58. 13.102
  libavdevice    58.  4.100 / 58.  4.100
  libavfilter     7. 21.100 /  7. 21.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
  libpostproc    55.  2.100 / 55.  2.100
Input #0, flv, from '.\video.flv':
  Metadata:
    audiodelay      : 0
    canSeekToEnd    : 1
    creationdate    : Fri Feb 03 11:52:46 2006
                    :
  Duration: 00:00:16.92, start: 0.000000, bitrate: 316 kb/s
    Stream #0:0: Audio: mp3, 22050 Hz, stereo, fltp, 40 kb/s
    Stream #0:1: Video: vp6f, 1 reference frame, yuv420p, 360x288 (368x288), 266 kb/s, 25 fps, 25 tbr, 1k tbn
Stream mapping:
  Stream #0:1 -> #0:0 (vp6f (native) -> h264 (libx264))
  Stream #0:0 -> #0:1 (mp3 (mp3float) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
[graph_1_in_0_0 @ 0000020c0bcc4200] tb:1/22050 samplefmt:fltp samplerate:22050 chlayout:0x3
[format_out_0_1 @ 0000020c0bca2cc0] auto-inserting filter 'auto_resampler_0' between the filter 'Parsed_anull_0' and the filter 'format_out_0_1'
[auto_resampler_0 @ 0000020c0bca5140] ch:2 chl:stereo fmt:fltp r:22050Hz -> ch:2 chl:stereo fmt:fltp r:44100Hz
[graph 0 input from stream 0:1 @ 0000020c0c4f4600] w:360 h:288 pixfmt:yuv420p tb:1/1000 fr:25/1 sar:0/1 sws_param:flags=2
[scaler_out_0_0 @ 0000020c0c4f73c0] w:426 h:240 flags:'bicubic' interl:0
[scaler_out_0_0 @ 0000020c0c4f73c0] w:360 h:288 fmt:yuv420p sar:0/1 -> w:426 h:240 fmt:yuv420p sar:0/1 flags:0x4
[libx264 @ 0000020c0bc80600] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0000020c0bc80600] profile Constrained Baseline, level 3.0
[libx264 @ 0000020c0bc80600] 264 - core 155 r2901 7d0ff22 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=7 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=30 keyint_min=3 scenecut=40 intra_refresh=0 rc_lookahead=10 rc=abr mbtree=1 bitrate=400 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=1500 vbv_bufsize=6000 nal_hrd=none filler=0 ip_ratio=1.40 aq=1:1.00
Output #0, flv, to 'rtmp://live-api.facebook.com:80/rtmp/my key:
  Metadata:
    audiodelay      : 0
    canSeekToEnd    : 1
    creationdate    : Fri Feb 03 11:52:46 2006
                    :
    encoder         : Lavf58.13.102
    Stream #0:0: Video: h264 (libx264), 1 reference frame ([7][0][0][0] / 0x0007), yuv420p, 426x240, q=-1--1, 400 kb/s, 30 fps, 1k tbn, 30 tbc
    Metadata:
      encoder         : Lavc58.19.101 libx264
    Side data:
      cpb: bitrate max/min/avg: 1500000/0/400000 buffer size: 6000000 vbv_delay: -1
    Stream #0:1: Audio: mp3 (libmp3lame) ([2][0][0][0] / 0x0002), 44100 Hz, stereo, fltp, delay 1105, 128 kb/s
    Metadata:
      encoder         : Lavc58.19.101 libmp3lame
No more output streams to write to, finishing.e=00:00:16.51 bitrate= 533.3kbits/s speed=0.992x
[flv @ 0000020c0bc97fc0] Failed to update header with correct duration.
[flv @ 0000020c0bc97fc0] Failed to update header with correct filesize.
frame=  424 fps= 25 q=-1.0 Lsize=    1153kB time=00:00:16.95 bitrate= 557.1kbits/s speed=0.997x
video:869kB audio:265kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.666647%
Input file #0 (.\video.flv):
  Input stream #0:0 (audio): 649 packets read (84767 bytes); 649 frames decoded (373824 samples);
  Input stream #0:1 (video): 424 packets read (566376 bytes); 424 frames decoded;
  Total: 1073 packets (651143 bytes) demuxed
Output file #0 (rtmp://live-api.facebook.com:80/rtmp/my key):
  Output stream #0:0 (video): 424 frames encoded; 424 packets muxed (889641 bytes);
  Output stream #0:1 (audio): 649 frames encoded (747648 samples); 650 packets muxed (271673 bytes);
  Total: 1074 packets (1161314 bytes) muxed
[libx264 @ 0000020c0bc80600] frame I:18    Avg QP:27.75  size:  7001
[libx264 @ 0000020c0bc80600] frame P:406   Avg QP:32.67  size:  1879
[libx264 @ 0000020c0bc80600] mb I  I16..4: 39.3%  0.0% 60.7%
[libx264 @ 0000020c0bc80600] mb P  I16..4:  8.3%  0.0%  2.3%  P16..4: 42.2% 16.2%  4.4%  0.0%  0.0%    skip:26.6%
[libx264 @ 0000020c0bc80600] final ratefactor: 28.61
[libx264 @ 0000020c0bc80600] coded y,uvDC,uvAC intra: 40.2% 33.7% 9.2% inter: 23.8% 7.5% 0.2%
[libx264 @ 0000020c0bc80600] i16 v,h,dc,p: 24% 50% 20%  6%
[libx264 @ 0000020c0bc80600] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 13% 34% 18%  5%  5%  4%  8%  4%  8%
[libx264 @ 0000020c0bc80600] i8c dc,h,v,p: 67% 24%  7%  2%
[libx264 @ 0000020c0bc80600] kb/s:418.33```

这张图片显示，这条流在Facebook上存活了几秒钟

```[flv @ 0000020c0bc97fc0] Failed to update header with correct duration.

flv @ 0000020c0bc97fc0未能用正确的文件大小更新标头。`

请纠正我，上面列出的日志错误，似乎是视频在几秒钟后停止播放的主要原因。我已经检查了延迟问题，但无论如何也帮不上忙。

请帮我解决这个问题。我会非常感激的。*‘)

流甚至更早结束，当我使用谷歌计算引擎，而不是我自己的个人电脑作为流媒体服务。

Answer 1

在修改flv文件的末尾，FFmpeg用持续时间和文件大小值更新头(文件前面)。然而，当您正在流，ffmpeg不能寻求到前面，所以警告会显示。

您可以通过添加一个标志(-flvflags no_duration_filesize)来禁用此函数，例如：

ffmpeg -re -i SampleM.flv -acodec libmp3lame -ar 44100 -b:a 128k \
  -pix_fmt yuv420p -profile:v baseline -s 426x240 -bufsize 6000k \
  -vb 400k -maxrate 1500k -deinterlace -vcodec libx264           \
  -preset veryfast -g 30 -r 30 -f flv                            \
  -flvflags no_duration_filesize                                 \
  "rtmp://live-api.facebook.com:80/rtmp/my_key"