[Asterisk-video] mp4save(): different audio and video lengths

[Sven Brandau]

Hi Sergio, Hi @All,

I think the solution that introduced by me works fine on none error prone channels.

In case of errors or lost frames the patch will not have any impact. I 
understand that the adaption layer 2 for audio (AL2) and layer 3 for video (AL3) 
of H.324M can be used with optional sequence numbers (SN). By using sequence 
numbers, the receiver can detect lost frames.

But the use of SN is optional and depends on the implementation of the H.324M 
stack on the mobile phone. If the phone doesn't support SN's we can't retrieve 
lost frames.

In terms of the problem here with desynchronized audio/video or different 
lengths of audio/video, I guess we could solve it only on phones that supports 
sequence numbers.

Am I right?

Best regards,
Sven


Sergio Garcia Murillo wrote:
> Yes, please, if anyone test it, send the results to the list so we can 
> commit the patch to the repository.
> A priori I see it quite clea, so I think it won't do any harm at all 
> (another issue is if it solves the problem :)
> 
> BR
> Sergio
> 
> Sven Brandau escribió:
>> Hi @All,
>>
>> recording to the questions, I've send you my patch.
>>
>> Please note that the patch is NOT really tested - please try it
>> and send me your results.
>>
>> Patch it with (R213):
>> patch -i app_h324m.c.patch
>>
>> Regards,
>> Sven
>>
>>
>>
>>
>> Sergio Garcia Murillo wrote:
>>> Hi Sven
>>>
>>> Could you send me a patch with oyour solution?
>>>
>>> BR
>>> Sergio
>>>
>>> ----- Original Message -----
>>> From: Sven Brandau [mailto:brandau at gmx.de]
>>> To: asterisk-video at lists.digium.com
>>> Sent: Mon, 05 May 2008 15:30:33 +0200
>>> Subject: Re: [Asterisk-video] mp4save(): different audio and video 
>>> lengths
>>>
>>> Hi @All,
>>>
>>> I'm working on a solution.
>>>
>>> I've found that some mobile phones (Moto K3) sending out AMR No-Data
>>> packets, instead of comfort noise frames (AMR-SID). So I replaced the
>>> No-Data packets with the last received AMR-SID frame (file app_h324m.c /
>>> function create_ast_frame). This solution worked fine for me.
>>>
>>> The only thing is, that the recording for audio and video starts on a
>>> different time - audio and video is already not synchronized, but only
>>> a few milliseconds. It depends on the mp4save option /V - waiting for 
>>> the
>>> first I-frame.
>>>
>>> I'm already working on this issue and will announce my solution here 
>>> on the
>>> mailing list.
>>>
>>> Regards,
>>> Sven
>>>
>>> Low Yu Siang wrote:
>>>> Hi,
>>>>
>>>> May I know if anyone has solved the recording
>>>> audio/video length problem?
>>>>
>>>> Tech from i6net wrote :
>>>>> Hi,
>>>>>
>>>>> I am going to work on it.
>>>>>
>>>>> But for the moment, I am qualifying the video transcoder and the 
>>>>> h324m module.
>>>>> The Gateway (SIP -> 3G or 3G -> SIP) configuration
>>>> locks after some secondes or minutes if it use the
>>>> transcoder.
>>>>> 2 ways for the recording :
>>>>> - Replace the silence by generating the AMR datas
>>>> with a audio silence.
>>>>> - Check if we can timestamps correctly the AMR
>>>> packets in the MP4/3GP hinted file.
>>>>
>