我正在尝试读取实时RTMP流，并使用以下命令将结果保存到文件中：
ffmpeg -re -rtmp_live live -y -i "rtmp://<server>/<app>/<stream>" -c copy -f flv /tmp/dump.flv
我运行此命令，然后在10-15秒后终止进程并检查/tmp/dump.flv。我试图这样做是为了进行流诊断（确定实时流的编码，比特率，分辨率，像素格式和关键帧间隔）
此命令的有效时间约为25-50％。当FFMPEG工作时，大约需要5秒钟才能连接到流，然后它开始将数据转储到磁盘。取消进程后，我可以在/tmp/dump.flv中找到几兆字节的视频数据，可以使用ffprobe对其进行探测。
命令失败时，它将进入两种失败状态之一：
stderr充满了一系列有关“缺少大小为X的访问单元中的图片”的消息，并且创建了输出文件/tmp/dump.flv，但其中包含0个字节
ffmpeg version 3.4.4-1~16.04.york0 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.10) 20160609
configuration: --prefix=/usr --extra-version='1~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
libavutil 55. 78.100 / 55. 78.100
libavcodec 57.107.100 / 57.107.100
libavformat 57. 83.100 / 57. 83.100
libavdevice 57. 10.100 / 57. 10.100
libavfilter 6.107.100 / 6.107.100
libavresample 3. 7. 0 / 3. 7. 0
libswscale 4. 8.100 / 4. 8.100
libswresample 2. 9.100 / 2. 9.100
libpostproc 54. 7.100 / 54. 7.100
[NULL @ 0x55b72d568920] pps_id 381 out of range
[AVBSFContext @ 0x55b72d5692c0] Invalid NAL unit 0, skipping.
Last message repeated 1 times
[h264 @ 0x55b72d568920] Invalid NAL unit 0, skipping.
Last message repeated 1 times
[h264 @ 0x55b72d568920] no frame!
[h264 @ 0x55b72d568920] missing picture in access unit with size 2200
[AVBSFContext @ 0x55b72d5692c0] Invalid NAL unit 0, skipping.
Last message repeated 2 times
[h264 @ 0x55b72d568920] Invalid NAL unit 0, skipping.
Last message repeated 2 times
[h264 @ 0x55b72d568920] no frame!
[h264 @ 0x55b72d568920] missing picture in access unit with size 3171
[AVBSFContext @ 0x55b72d5692c0] Invalid NAL unit 0, skipping.
[h264 @ 0x55b72d568920] Invalid NAL unit 0, skipping.
[h264 @ 0x55b72d568920] no frame!
[NULL @ 0x55b72d568920] missing picture in access unit with size 80572
[h264 @ 0x55b72d568920] missing picture in access unit with size 1560
[h264 @ 0x55b72d568920] missing picture in access unit with size 2608
[h264 @ 0x55b72d568920] non-existing PPS 0 referenced
[h264 @ 0x55b72d568920] missing picture in access unit with size 2734
[h264 @ 0x55b72d568920] missing picture in access unit with size 2885
[h264 @ 0x55b72d568920] missing picture in access unit with size 77739
[h264 @ 0x55b72d568920] non-existing PPS 254 referenced
[h264 @ 0x55b72d568920] missing picture in access unit with size 3360
[h264 @ 0x55b72d568920] missing picture in access unit with size 2804
[h264 @ 0x55b72d568920] missing picture in access unit with size 3051
[h264 @ 0x55b72d568920] missing picture in access unit with size 3067
[h264 @ 0x55b72d568920] missing picture in access unit with size 77693
[h264 @ 0x55b72d568920] non-existing PPS 0 referenced
[h264 @ 0x55b72d568920] missing picture in access unit with size 2421
[h264 @ 0x55b72d568920] missing picture in access unit with size 2779
[h264 @ 0x55b72d568920] missing picture in access unit with size 2442
[h264 @ 0x55b72d568920] missing picture in access unit with size 2678
[h264 @ 0x55b72d568920] missing picture in access unit with size 76877
[h264 @ 0x55b72d568920] sps_id 15 out of range
[h264 @ 0x55b72d568920] missing picture in access unit with size 1342
[h264 @ 0x55b72d568920] missing picture in access unit with size 2412
[h264 @ 0x55b72d568920] missing picture in access unit with size 2238
[h264 @ 0x55b72d568920] missing picture in access unit with size 3550
[h264 @ 0x55b72d568920] missing picture in access unit with size 3075
...
(after hitting Ctrl+C:)
Input #0, flv, from 'rtmp://<server>/<app>/<stream>':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf57.83.100
Duration: 00:00:00.00, start: 5285.919000, bitrate: N/A
Stream #0:0: Video: h264 (Constrained Baseline), yuv420p, 1920x1080, 2543 kb/s, 24 fps, 24 tbr, 1k tbn, 48 tbc
Output #0, flv, to '/tmp/dump.flv':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf57.83.100
Stream #0:0: Video: h264 (Constrained Baseline) ([7][0][0][0] / 0x0007), yuv420p, 1920x1080, q=2-31, 2543 kb/s, 24 fps, 24 tbr, 1k tbn, 1k tbc
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame= 0 fps=0.0 q=-1.0 Lsize= 0kB time=00:00:00.00 bitrate=N/A speed= 0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Exiting normally, received signal 2.
消息“未找到起始代码”。会显示，并且FFMPEG会在不到半秒后立即终止。发生这种情况时，不会创建文件/tmp/dump.flv。
ffmpeg version 3.4.4-1~16.04.york0 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.10) 20160609
configuration: --prefix=/usr --extra-version='1~16.04.york0' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
libavutil 55. 78.100 / 55. 78.100
libavcodec 57.107.100 / 57.107.100
libavformat 57. 83.100 / 57. 83.100
libavdevice 57. 10.100 / 57. 10.100
libavfilter 6.107.100 / 6.107.100
libavresample 3. 7. 0 / 3. 7. 0
libswscale 4. 8.100 / 4. 8.100
libswresample 2. 9.100 / 2. 9.100
libpostproc 54. 7.100 / 54. 7.100
[NULL @ 0x56274b0be920] missing picture in access unit with size 3710
[AVBSFContext @ 0x56274b0bf2c0] No start code is found.
rtmp://<server>/<app>/<stream>: could not find codec parameters
Input #0, flv, from 'rtmp://<server>/<app>/<stream>':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf57.83.100
Duration: 00:00:00.00, start: 0.000000, bitrate: N/A
Stream #0:0: Video: h264, none, 2543 kb/s, 24 fps, 1k tbn
Output #0, flv, to '/tmp/dump.flv':
Output file #0 does not contain any stream
-re以尝试将输入帧速率限制为源帧速率-rtmp_live live -timeout 5（或其他任何超时值）-i "rtmp://<server>/<app>/<stream> live=1 timeout=5"）有人知道为什么此命令的成功如此断断续续吗，或者我如何获得更一致的结果？
我完全使用ffmpeg将流转储到临时文件的唯一原因是因为我计划对该文件执行多项测试（目前至少要进行两次测试-一个用于获取编码，另一个获取关键帧间隔）。通过下载流，我减少了带宽使用并减少了运行时间。但是，如果有帮助，放弃ffmpeg并直接在RTMP URL上使用ffprobe是完全可以接受的。
请注意，我确实尝试过此方法，并且使用ffprobe
答案 0 :(得分：0)
将Red5 v5.0.1用于RTMP服务器时出现这些错误。更新到Red5 v5.2.0可以解决此问题。这只是他们服务器中的错误。不知道出什么问题了，但是现在更好了。