ffmpeg无法识别视频中的音频流 [英] ffmpeg does not recognize audio stream in video

问题描述

我有这些从Adobe Connect导出的flv文件，我想用ffmpeg提取其音频.ffmpeg无法识别其中某些音频.此日志来自一个有问题的文件:

I have these flv files that exported from Adobe Connect and I want to extract their audio with ffmpeg. ffmpeg does not recognize the audio on some of them. This log is from one file that has issues:

>ffmpeg.exe -i r7anupl75gl_0_1965937.flv test1.mp3
ffmpeg version N-76123-g002b049 Copyright (c) 2000-2015 the FFmpeg                                                                      
built with gcc 5.2.0 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads                    
libavutil      55.  4.100 / 55.  4.100
libavcodec     57.  7.100 / 57.  7.100
libavformat    57.  8.102 / 57.  8.102
libavdevice    57.  0.100 / 57.  0.100
libavfilter     6. 11.100 /  6. 11.100
libswscale      4.  0.100 /  4.  0.100
libswresample   2.  0.100 /  2.  0.100
libpostproc    54.  0.100 / 54.  0.100
[flv @ 0000000000522140] Could not find codec parameters for stream 1        

(Audio: none, 0 channels): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize'   
options
Input #0, flv, from 'r7anupl75gl_0_1965937.flv':
Metadata:
lasttimestamp   : 5026
lastkeyframetimestamp: 5022
audiodelay      : 0
canSeekToEnd    : false
creationdate    : unknown
metadatacreator : Manitu Group FLV MetaData Injector 2
videosize       : 251586025
audiosize       : 55776880
datasize        : 516
Duration: 01:23:47.75, start: 0.000000, bitrate: 489 kb/s
Stream #0:0: Video: vp6f, yuv420p, 1184x704, 1k tbr, 1k tbn, 1k tbc
Stream #0:1: Audio: none, 0 channels
Output #0, mp3, to 'test1.mp3':
Output file #0 does not contain any stream

注意:音频编解码器是Nellymoser Asao，此命令对某些文件成功运行.

Note: audio codec is Nellymoser Asao and this command works successfully for some files.

推荐答案

考虑增加"analyzeduration"和"probesize"的值

Consider increasing the value for the 'analyzeduration' and 'probesize'

问题是在前10至15分钟内，flv文件实际上没有任何音频.通过增加 probesize 和 analyzeduration ，它可以在文件中更进一步地查找和检测音频.

The problem is in first 10-15 min the flv file doesn't actually have any audio. By increasing probesize and analyzeduration it looks further in the file to find audio and detect it.

在我的情况下，我必须将 analyzeduration 设置为大于5000000(5秒).

In my scenario I have to set analyzeduration bigger than 5000000 (5 seconds).

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