[Qt-interest] jerkiness in video on using phonon on windows

[Kunal Lagwankar]

Hi Jason,

Thanks for your response. We are working on some more observations 
related to your suggestions and will post results by tomorrow.
Thanks once again.

Kunal

Jason H wrote:
> Some questions/tests
>
> Is the QIODevice sequential? (socket?)
> With 2-3 second jerkiness, it sounds like the codec (or i/o) is going back to the last I frame after exhausting P frames. Can you transcode it to be all I frames?
> I think it may  be a problem with a partial read (in that you don't have a complete I/P frame) and that the Codec is resuming from the last I-frame. Meanign to me, it could be a buffering problem. Which then begs the question, if the media in a QBuffer? Does it work when it is?
>
>
>
>
>
> ----- Original Message ----
> From: Kunal Lagwankar <kunal at novix.in>
> To: qt-interest at trolltech.com
> Sent: Fri, November 20, 2009 9:55:25 AM
> Subject: [Qt-interest] jerkiness in video on using phonon on windows
>
> Hi,
>
> We are subclassing QIODevice to pass audio-video data to a custom parser 
> (a Directshow filter implementation) using Phonon. Phonon creates a 
> graph that includes the custom parser and corresponding audio-video 
> decoders and rendering filters. The custom parser internally separates 
> audio and video, which is then decoded and rendered.
> When this sequence is played, jerkiness is observed periodically (spaced 
> every 2-3 seconds). By video jerkiness, I mean that previous frame is 
> again rendered causing a break in continuous viewing. It is important to 
> note that there is no break in audio.
>
> When the same file with the custom format is drag-n-dropped in to 
> Graphedit, it automatically creates a pipeline and renders audio-video 
> data satisfactorily (meaning no jerkiness and in audio-video 
> synchronization). From this, we have concluded that the directshow 
> filters by themselves do not have any bug and perform correctly.
>
> We are unable to figure out why this behaviour is observed on using 
> phonon in windows. Any help/suggestions in this matter will be appreciated.
>
> Thanks.
>
> Kunal
>
> _______________________________________________
> Qt-interest mailing list
> Qt-interest at trolltech.com
> http://lists.trolltech.com/mailman/listinfo/qt-interest
>
>
>
>       
>   
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com 
> Version: 8.5.425 / Virus Database: 270.14.76/2517 - Release Date: 11/21/09 07:47:00
>
>