MiniDLNA Transcode - Hardware MPEG-2 Encoding?


9 posts
by Jademalo » Mon Mar 11, 2013 3:54 pm
I've got a few questions related to this.

1. Has Mencoder/FFMpeg stated that they will update to support the GPU encoding features of the pi?
2. The codecs in the store - are they only for hardware encode/decode, or does it limit software encode/decode too?
3. Why does a standard desktop not require purchasing additional codecs before they work?

I've managed to get it converting at about 13fps, if I could just eek a bit more out I might be able to do it.
Posts: 12
Joined: Tue Feb 26, 2013 8:02 pm
by Jademalo » Wed Mar 13, 2013 9:05 pm
Been reading around, still cant find any more info or answers on my question.
Posts: 12
Joined: Tue Feb 26, 2013 8:02 pm
by ghans » Wed Mar 13, 2013 11:14 pm
1) Nope. We have a "omxtx" proof-of-concept transcoder though.
NOTE : Both the OpenMAX API and libraries are cost-free
and open , but that doesn't seem to have helped much.
2) Hardware only.
3) This thread shows some very good arguments :
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=4704#p62978
And AFAIK the foundation is trying hard not to get sued.


The point is : The CPU of the Pi is simply too slow for
software en/trans/decode.


ghans
• Don't like the board ? Missing features ? Change to the prosilver theme ! You can find it in your settings.
• Don't like to search the forum BEFORE posting 'cos it's useless ? Try googling : yoursearchtermshere site:raspberrypi.org
Posts: 4881
Joined: Mon Dec 12, 2011 8:30 pm
Location: Germany
by Jademalo » Thu Mar 14, 2013 2:22 pm
Brilliant answers, thank you!

With regards to point 3 - Does that mean normal PCs don't need them due to everything being done in software, since as you said in point 2 the codecs in the store are only for a hardware encode license?
Posts: 12
Joined: Tue Feb 26, 2013 8:02 pm
by jamesh » Thu Mar 14, 2013 2:36 pm
Jademalo wrote:Brilliant answers, thank you!

With regards to point 3 - Does that mean normal PCs don't need them due to everything being done in software, since as you said in point 2 the codecs in the store are only for a hardware encode license?


Sort of. Technically, SW codecs should also pay the licence, but that has never been/is impossible to enforce. With HW codecs, it's easy for MPEGLA to say - that's on, you owe us
Volunteer at the Raspberry Pi Foundation, helper at Picademy September, October, November 2014.
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 12359
Joined: Sat Jul 30, 2011 7:41 pm
by Jademalo » Thu Mar 14, 2013 4:31 pm
Aaah, I see.

Is that one of the reasons why the high end encoding software like Premiere etc. are so expensive? Since they have to licence the codecs properly?
Posts: 12
Joined: Tue Feb 26, 2013 8:02 pm
by jamesh » Thu Mar 14, 2013 4:37 pm
Jademalo wrote:Aaah, I see.

Is that one of the reasons why the high end encoding software like Premiere etc. are so expensive? Since they have to licence the codecs properly?


No, the actual licences fees are pretty low, just a few dollars/device. But because even a few dollars is a good percentage of the Raspi selling price, we don't put them all on as standard. I guess the high end encoders are expensive because they are very effective - i.e. better compression ratios for similar quality levels. But that is a guess.
Volunteer at the Raspberry Pi Foundation, helper at Picademy September, October, November 2014.
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 12359
Joined: Sat Jul 30, 2011 7:41 pm
by Jademalo » Thu Mar 14, 2013 6:17 pm
Oh, that makes sense. Pure proportion.

One last question - Are hardware encoding licenses based on the chip that is doing the encoding, the device as a whole, or is it related to the user? (I'm assuming chip - but I was curious if it was in any way transferable)
Posts: 12
Joined: Tue Feb 26, 2013 8:02 pm
by drgeoff » Thu Mar 14, 2013 7:07 pm
jamesh wrote:
Jademalo wrote:Aaah, I see.

Is that one of the reasons why the high end encoding software like Premiere etc. are so expensive? Since they have to licence the codecs properly?


No, the actual licences fees are pretty low, just a few dollars/device. But because even a few dollars is a good percentage of the Raspi selling price, we don't put them all on as standard. I guess the high end encoders are expensive because they are very effective - i.e. better compression ratios for similar quality levels. But that is a guess.

High end encoders are expensive because:
1. The market is relatively small so when the development cost is spread across the number of units sold it adds a lot.
2. Users of high end encoders are usually both able and prepared to pay the high prices. :)

Bear in mind that the MPEG video specs really only define how a coded bit-stream should be 'interpreted' by a decoder. There is a great deal of scope for two different encoders to take the same video input signal and produce two encoded versions from which a decoder can reconstruct two approximations to the original. But the bit-rate versus subjective quality characteristics of the two can be very different.
Posts: 3140
Joined: Wed Jan 25, 2012 6:39 pm