[FFmpeg-user] -qscale:a and -write_xing 0 can't be used at same time?

[桃源老師]

Additional information...

Not related with original question, but to understand the work-around "-write_xing 0"...

> 2017/01/28 6:56 A.M. 桃源老師 <xanadu6291 at dream.jp> wrote:
> 
> My understanding for ffmpeg's option "-write_xing 0" is to instruct not to write Xing header to result file(s).  If it is correct, I wonder why ffmpeg's default CBR file's duration can be fixed in Mac/iTunes.
> 
> Also, I feel doubt for your comment Mac/iTunes can't cope well with Xing headers.  The reason is below...

> I now understand "-qscale:a" and "-write_xing 0" should not be used at the same time. And confirmed that Mac/iTunes understand duration correctly with "-qscale:a" only...
> I think this means that Mac/iTunes can handle Xing header, doesn't it?

I checked some mp3 files with binary editor.  The results are as follows:

1. a mp3 produced by ffmpeg's default command does not have xing header.
2. a mp3 produced by ffmpeg's default command + write_xing 0 also does not have xing header.
3. a mp3 produced by ffmpeg with qscale:a 2 have xing header.
4. a mp3 produced by lame -V 2 option have xing header.
5. a mp3 produced by lame -b 128 option does not have xing header.

In all 5 files, only No.1's duration is double sized in Mac/iTunes.

I  also checked above mp3s with mpg123.  The results are as follows:

1. a mp3 produced by ffmpeg's default command recognized as VBR.
2. a mp3 produced by ffmpeg's default command + write_xing 0 recognized as CBR128.
3. a mp3 produced by ffmpeg with qscale:a 2 recognized as VBR.
4. a mp3 produced by lame -V 2 option have xing header. recognized as VBR.
5. a mp3 produced by lame -b 128 option does not have xing header. recognized as CBR128.

I now see the reason why "No.1's duration is double sized in Mac/iTunes" is VBR!

Am I doing any wrong?


Best Regards,

// Miya aka. TougenRoushi
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