[mpeg2] Hardware Mpeg2 Encoding

Johannes Stezenbach js at linuxtv.org
Tue Aug 2 15:30:48 CEST 2005


On Thu, Jul 28, 2005 sebastien Pastor wrote:
> I ve been asked to produce some Mpeg2-TS output (this output will be 
> carried out by our satellite provider). The video sources i have are DV 
> files. So i thought i could use ffmpeg to transcode to MPEG2 PS then VLC 
> to convert into TS but ... our satellite provider requirements are 
> strict  : they want : 2500Kb/s rate in CBR.. Using ffmpeg the result is 
> not sooo good (many artifacts visible) and even after fiddling around 
> with the thousands of mpeg2 options i can t get a good result .... So i 
> thought i ve reached the limit of software encoding ... ?
> So here are my questions to you mpeg2 experts : do you think if i move 
> to an mpeg2 compression card i should be able to get better results even 
> @ low rates with strict CBR ? Would you recommend a card for this 
> purpose ? Have heard about the hauppauge 350 card, do you reckon i 
> should go for this (even it looks like it is a TV Tuner as well ...) ? 
> If yes how could i proceed to make the card compress my DV files (using 
> VLC ?)

I don't know much about mpeg encoding, but I think consumer grade
hardware encoders won't give you the best possible quality, because
they need to encode in real time, but have limited processing power.

ffmpeg or other encoders should be able to give you better results, but
I think they won't give you strict bitrates even in CBR mode. You would
need to do a few experiments to find a parameter setting to ensure
the maximum bitrate never exeeds your limit, while still using
as much as possible of the available bandwidth, and add some
stuffing later to ensure the reulting stream has strict CBR.

I don't know if there is an OpenSource tool to do that. Usually the
broadcasters have tools to do that, though.

HTH,
Johannes



More information about the mpeg2 mailing list