[Live-devel] Regarding MP3 Streaming

[Nikhil Agrawal]

Hi Ross,

Thanks Ross, I have still 2 Queries :-
Q1. If I dont need Fast Forward, just seek n pause is sufficient then also
do i need to convert MP3-> ADU -> MP3

Q2. This conversion is compulsory even if I just want to support Play. Or
its just for trick mode and no need if only playing need to be supported.

Thanks and Regards,
Nikhil Agrawal


On 2/18/07, Ross Finlayson <finlayson at live555.com> wrote:
>
>  I was working on MP3 streaming code and what I understood is first an MP3
> frame is converted to ADU and then again this ADU is converted to MP3 frame.
> Although I am still trying to understand the complete flow but can you tell
> me why we are doing this conversion from A -> B -> A . Is that just because
> to support trick mode or something else.
>
>
>
> (I presume you're referring to the "MP3AudioFileServerMediaSubsession"
> code.)
>
>
> Yes, the conversion MP3->ADU->MP3 is done in order to support 'trick mode'
> - specifically, fast forward.  Because MP3 frames are not self contained, it
> is not possible to implement Nx speedup on a MP3 stream simply by extracting
> every Nth MP3 frame.  Instead, we need to first convert to ADUs, apply the
> scaling on the ADUs, and then convert them back to MP3 frames.
>
>
> (For more information on MP3 ADUs, see <http://www.live555.com/rtp-mp3/>
> and <http://www.live555.com/rtp-mp3/rtp-mp3.txt>
>
> --
>
>
> Ross Finlayson
> Live Networks, Inc.
> http://www.live555.com/
>
> _______________________________________________
> live-devel mailing list
> live-devel at lists.live555.com
> http://lists.live555.com/mailman/listinfo/live-devel
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.live555.com/pipermail/live-devel/attachments/20070218/3b90dfec/attachment.html