[FFmpeg-user] Strange output of ffprobe

[Анатолий Коростелев]

Hello!

How did you see missing of the AudioSpecificConfig in the file? It will 
be very useful for me to detect such bad files in the future.


28.10.16 12:09, Анатолий Коростелев пишет:
> > 48000 Hz seems the correct one, so no FFmpeg bug but MediaInfo bug 
> (as a first shot, issue is that there is an ES descriptor without 
> AudioSpecificConfig element in the track header and MediaInfo does not 
> manage correctly this case; note that this may be the reason some 
> players does not play sound).
>
> Under the absence of the AudioSpecificConfig element in the track 
> header do you mean to the absence of the "Format profile" field of the 
> medianfo output? I've looked at the difference between mediainfo 
> output of this bad mp4 file and a good mp4 file and I've found that 
> the good one contains "Format profile":
>
> diff -u mediainfo_output_of_bad_file mediainfo_output_of_good_file:
>
> ...
>
>  Audio
>  ID                                       : 2
> -Format                                   : ER Parametric
> +Format                                   : AAC
>  Format/Info                              : Advanced Audio Codec
> +Format profile                           : LC
>  Codec ID                                 : 40
>  Duration                                 : 22 min 49 s
>  Bit rate mode                            : Constant
>  Bit rate                                 : 128 kb/s
>  Channel(s)                               : 2 channels
> -Sampling rate                            : 7 350 Hz
> -Frame rate                               : 7.178 FPS (1024 spf)
> +Channel positions                        : Front: L R
> +Sampling rate                            : 48.0 kHz
> +Frame rate                               : 46.875 FPS (1024 spf)
>  Compression mode                         : Lossy
>  Stream size                              : 21.0 MiB (38%)
>  Default                                  : Yes
>  Alternate group                          : 1
>
> ...
>
> 28.10.16 0:11, Jerome Martinez пишет:
>> Le 27/10/2016 à 18:06, Анатолий Коростелев a écrit :
>>> Hello!
>>>
>>> Recently I recieved a mp4 for playing. When I tried to play this 
>>> file I didn't hear any sound in some players (in ffplay sound 
>>> worked). When I looked at the metadata of this file (via ffprobe), I 
>>> saw the following:
>>>
>>> [...]
>>>
>>> Then I used mediainfo utility to see the metadata of the file:
>>>
>>> [...]
>>>
>>>
>>> As you can see the "Sampling rate" in mediainfo is 7 350 Hz (it's 
>>> illegal value) 
>>
>> It is not an illegal value, AAC specs authorize it.
>>
>>> while "Sampling rate" in ffprobe is 48000 Hz. I think that the 
>>> problem with the sound of this file has been caused by encoder 
>>> errors/misconfiguration. But it's very strange that ffrobe always 
>>> shows me 48000 Hz Sampling rate. Is this a bug or something else?
>>
>> 48000 Hz seems the correct one, so no FFmpeg bug but MediaInfo bug 
>> (as a first shot, issue is that there is an ES descriptor without 
>> AudioSpecificConfig element in the track header and MediaInfo does 
>> not manage correctly this case; note that this may be the reason some 
>> players does not play sound).
>>
>> Jérôme, developer of MediaInfo.
>>
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>

-- 
С уважением,
Коростелев Анатолий