[Asterisk-video] MP4Play async Audio / Video
Klaus Darilion
klaus.mailinglists at pernau.at
Tue Sep 25 10:09:21 CDT 2007
Which parameters have you used for encoding with ffmpeg?
Thomas Z. schrieb:
> Hi Sergio,
>
> thank you very much. The result with the Helix Mobile Producer is much
> better.
> But we need a software runs on a Linux environment.
> Can you support us with a another linux software?
>
> Regards
> Thomas
>
>
> Sergio Garcia schrieb:
>> You coulde try with qt encoder or the helix mobile producer..
>>
>> ---------- Original Message ----------------------------------
>> From: "Thomas Z." <mobilemail at gmx-topmail.de>
>> Reply-To: Development discussion of video media support in Asterisk<asterisk-video at lists.digium.com>
>> Date: Tue, 25 Sep 2007 10:52:07 +0200
>>
>>
>>> Hello Sergio,
>>>
>>> do you know a freeware or cheap CBR encoder?
>>>
>>> Regards
>>> Thomas
>>>
>>> Sergio Garcia Murillo schrieb:
>>>
>>>> Hi Thomas, Thomas and Ratmin.. :)
>>>>
>>>> Back to work form a long abroad weekend (nice Belgium!)
>>>>
>>>> As Ratmin has stated the Skew indication would help to indicate the
>>>> handset the delay between audio and video.
>>>> It's usually used to correct fixed delays introduced by internal
>>>> jitter buffers and thinks alike. The problem that Thomas
>>>> Z. is suffering seems to be produced by using ffmpeg for video
>>>> encoding (as Thomas without Z points :)
>>>> The problem is the following, ffmpeg is a great VBR (variable bit
>>>> rate) encoder, but I've not been able to behave like a
>>>> CBR (constant bit rate) encoder. The problem is that it's prepared for
>>>> movies, not for streaming, and defenitevilly not
>>>> at this low bitrates.
>>>> The inner loop of the encoder always tries to encode ALL macroblocks
>>>> in a frame, so in I frames and at a very low
>>>> bitrate it simply just can't get a small amount of data for that frame
>>>> and when it's enqued into h324m it takes more
>>>> than one frame time to send (sometimes even more than a second), the
>>>> following frames are small and sent after
>>>> that until the queue is empty, which causes a fast-forward effect
>>>> on some handsets. As you can imagine adjustime
>>>> audio to that scenary is jus impossible (even with the Skew Indication
>>>> the result would be horrible!!)
>>>>
>>>> The good solution: use a CBR encoder :)
>>>> The not so good solution: drop packets when the queue is filled, but
>>>> you'll end up dropping all the frames between
>>>> each I frame.. but in that case it would be much better to lower the
>>>> video fps...
>>>>
>>>> BR
>>>> Sergio
>>>>
>>>> ----- Original Message -----
>>>> *From:* Ramtin Amin <mailto:keytwho at hotmail.com>
>>>> *To:* Development discussion of video media support in Asterisk
>>>> <mailto:asterisk-video at lists.digium.com>
>>>> *Sent:* Monday, September 24, 2007 2:01 PM
>>>> *Subject:* Re: [Asterisk-video] MP4Play async Audio / Video
>>>>
>>>>
>>>>
>>>>
>>>> RTSP has timestamp... so you can usually know how to sync the
>>>> audio/video
>>>> But the problem would be more that we'll need to add a Skew
>>>> Indication concept inside asterisk's core so it could make the
>>>> message go throught the different channel/application, as it is
>>>> currently done for VideoFastUpdatePicutre... Which means that
>>>> currently, if a SIP channel receives a VideoFastUpdatePicture, it
>>>> is capable of resending it to an other channel...
>>>>
>>>>
>>>> ------------------------------------------------------------------------
>>>>
>>>> > Date: Mon, 24 Sep 2007 13:48:54 +0200
>>>> > From: mobilemail at gmx-topmail.de
>>>> > To: asterisk-video at lists.digium.com
>>>> > Subject: Re: [Asterisk-video] MP4Play async Audio / Video
>>>> >
>>>> > Hello Ramin,
>>>> > hello Thomas.
>>>> >
>>>> > I think both ways are possible. But I don't know if it easy to
>>>> implement.
>>>> > Sergio, what do you think about it?
>>>> >
>>>> > Is this also a problem if we stream the audi/video via rtsp?
>>>> >
>>>> > Regrads
>>>> > Thomas
>>>> >
>>>> >
>>>> > Ramtin Amin schrieb:
>>>> > > hello
>>>> > >
>>>> > > The way I solved this problem was by sending a H223SkewIndication
>>>> > > message to the other terminal
>>>> > > Acutally, You will have to ask Sergio to add a H245 indication
>>>> message
>>>> > > of type h223SkewIndication and when playing the video with
>>>> mp4play, he
>>>> > > will have to see the difference of timing between Video and
>>>> Audio and
>>>> > > then send this value to the remote terminal so the lip sync
>>>> would work...
>>>> > >
>>>> > >
>>>> > >
>>>> > > **
>>>> > >
>>>> > > *2.3 Multipoint Lip Synchronization*
>>>> > >
>>>> > > In a multipoint VC, each terminal may transmit different
>>>> > >
>>>> > > //
>>>> > >
>>>> > > /H223SkewIndication /message for associated video and
>>>> > >
>>>> > > audio channels in H.223 protocol. To enable lip
>>>> > >
>>>> > > synchronization at receiving terminals, MCUs will
>>>> > >
>>>> > > transmit accurate /H223SkewIndication /messages. MCUs
>>>> > >
>>>> > > may accomplish this by adding delay to equalize the
>>>> > >
>>>> > > audio/video skew for all transmitting terminals. When
>>>> > >
>>>> > > switching between broadcasting terminals, H.223 may
>>>> > >
>>>> > > transmit a new /H223SkewIndication /message reflecting the
>>>> > >
>>>> > > audio/video skew of the current broadcaster.
>>>> > >
>>>> > >
>>>> > > --
>>>> > > Ramtin Amin
>>>> > >
>>>> > >
>>>> > >
>>>> > >
>>>> > >
>>>> ------------------------------------------------------------------------
>>>> > >
>>>> > > > From: thomas.frieling at viif.de
>>>> > > > To: asterisk-video at lists.digium.com
>>>> > > > Date: Mon, 24 Sep 2007 11:48:12 +0200
>>>> > > > Subject: Re: [Asterisk-video] MP4Play async Audio / Video
>>>> > > >
>>>> > > > Hi Thomas Z!
>>>> > > >
>>>> > > > I think this problem is due to the bitrate restriction on 3G
>>>> calls. The
>>>> > > > audio stream is always sent immediately while the video
>>>> stream has to
>>>> > > > use what is left of the bandwidth. This is why videos become
>>>> synchrous
>>>> > > > again when the video bitrate is pretty low for a while in
>>>> the video...
>>>> > > >
>>>> > > > Take a look at this discussion:
>>>> > > >
>>>> > >
>>>> http://lists.digium.com/pipermail/asterisk-video/2007-September/001257.html
>>>> > > >
>>>> > > > One solution is to reencode every video with a low bitrate
>>>> and use a
>>>> > > > fixed bitrate encoder (ffmpeg is dynamic bitrate for
>>>> example). I had the
>>>> > > > impression though that this still doesn't always work,
>>>> especially when
>>>> > > > the UMTS connection is not too good...
>>>> > > >
>>>> > > > My idea is that we check each time before sending a keyframe
>>>> if there is
>>>> > > > already a new keyframe in the queue. If this is the case, we
>>>> jump to the
>>>> > > > most recent keyframe and just drop the data before that.
>>>> > > >
>>>> > > > What do you think about this? How hard to implement?
>>>> > > >
>>>> > > > Regards,
>>>> > > > Thomas F
>>>> > > >
>>>> > > >
>>>> > > >
>>>> > > > Am Montag, den 24.09.2007, 11:15 +0200 schrieb Thomas Z.:
>>>> > > > > Hello,
>>>> > > > >
>>>> > > > > We have the problem, that a converted mp4 file is
>>>> asynchronous via 3g
>>>> > > > > network.
>>>> > > > > If we play the file on a pc, everything is synchron.
>>>> > > > > We tried already to reduce the quality and framerate of
>>>> the video. But
>>>> > > > > nothing helps.
>>>> > > > >
>>>> > > > > Is it a problem with mp4play or with the video?
>>>> > > > >
>>>> > > > > What can we do to get the audio and video synchronized via
>>>> 3g network?
>>>> > > > >
>>>> > > > > Thank you,
>>>> > > > > best regards
>>>> > > > > Thomas
>>>> > > > >
>>>> > > > >
>>>> > > > >
>>>> > > > > _______________________________________________
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>>>> > > > --
>>>> > > > www.ViiF.de - your Mobile Video Community
>>>> > > >
>>>> > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>> > > >
>>>> > > > Thomas Frieling - IT Development
>>>> > > > ViiF Mobile Video GmbH, Poststr. 21-22, 10178 Berlin
>>>> > > > Cell: +49 (0) 173 63 62 62 3
>>>> > > >
>>>> > > > mailto:thomas at ViiF.de
>>>> > > >
>>>> > > > Sitz: Berlin, Amtgericht Berlin-Charlottenburg, HRB: 108350B
>>>> > > >
>>>> > > > Geschäftsführer: Daniel Höpfner, Steffen Brünn
>>>> > > >
>>>> > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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>>
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