AVI playback

[Datman]

About 1 month ago someone has stolen my Onda VX777 player (or it was a good imitation...). It wasn't a very good audio player, but it played big AVI (mpeg4/DivX) files without any problem. Does it have a video decoder chip, not present in my Sansa Fuzev2?

[soap]

I'm not 100% sure I'm reading the right implication into your question, but it appears to me you're saying the Onda played AVI with Rockbox.  Which it does not.

The Onda does play many types of AVI containered videos in its original firmware, though.
As to if it has a dedicated video decoder I can't say.  I do know that it was marketed as a media player (implying video) not just a MP3 player.

[Datman]

The Onda does play many types of AVI containered videos in its original firmware, though.
As to if it has a dedicated video decoder I can't say.  I do know that it was marketed as a media player (implying video) not just a MP3 player.

I was thinking about what someone said in this thread: power requested for mpeg-4 decoding is too high for "our" audio players. I think Onda media player have hardware video decoders, so that they don't rely on the CPU for decoding. An mp3 player has to do all by software & CPU.

[saratoga]

I was thinking about what someone said in this thread: power requested for mpeg-4 decoding is too high for "our" audio players. I think Onda media player have hardware video decoders, so that they don't rely on the CPU for decoding. An mp3 player has to do all by software & CPU.

I don't know anything about the Onda players, but searching google it says they use software decoding.  This seems reasonable, since google also only claims it can decode a few relatively simple video formats. 

[sirdan]

I was thinking about what someone said in this thread: power requested for mpeg-4 decoding is too high for "our" audio players.

Can anybody tell me, how mpeg-4 (SP particularly) can be more power demanding than mpeg-2? The former was designed specifically for mobile devices, while the latter for HIGH BITRATE dvd movies. Of course actual mpegplayer plugin is optimized, but imagine what could you do with mpeg-4 codec when giving it some atention. I guess this codec is optimized in its specification to run on mobile cpus. I think some pple still cant differ mpeg-4 SP from mpeg-4 ASP which is actually xvid/divx (sp + B-frames and more) and indeed at the begining mpeg4 ASP was more demanding than mpeg2 on PC. Its designed for SMALL BITRATE, thats why we can squeeze the file sizes with xvid even more than any mpeg2 encoder. Am i wrong?
EDIT: and i bet there should be some existing code to run xvid decoder at least on arm targets?

[saratoga]

I was thinking about what someone said in this thread: power requested for mpeg-4 decoding is too high for "our" audio players.

Can anybody tell me, how mpeg-4 (SP particularly) can be more power demanding than mpeg-2?

Is it actually more computationally complex?  I was under the impression that they're not terribly different.

[torne]

Very few people actually *use* MPEG-4 SP, is probably the reason. Adding it wouldn't solve the need to transcode everything, almost all MPEG-4 video out there is ASP.

And no, no version of MPEG is optimised in its specification for mobile CPUs.

MPEG-4 ASP implementations for ARM exist, sure, but they are more demanding than the majority of our players can support.

[sirdan]

Very few people actually *use* MPEG-4 SP, is probably the reason.

You mean AVI's on PC? Sure, why would any sacrifice b frames while nowadays its just so simple to decode it. But everybody use it on mobiles.

Adding it wouldn't solve the need to transcode everything, almost all MPEG-4 video out there is ASP.

You need to transcode to mpeg2 anyway. But, i sure pple still shoot small clips by cameras in cells in 3gp/h263 format. Thats more or less mpeg4 SP - link

And no, no version of MPEG is optimised in its specification for mobile CPUs.

Then i was wrong.

MPEG-4 ASP implementations for ARM exist, sure, but they are more demanding than the majority of our players can support.

Well asp should be marvellous, but i think, still with sp we can have some gain over mpeg2. I wrote mpeg4 sp is just about or little bit better than h263. Well i hope that woudnt be step back comparing to existing mpeg2 encoder used for mpegplugin And many existing 3gp/mp4 mobile recordings work just without recompression, just like that.

@saratoga

Is it actually more computationally complex? I was under the impression that they're not terribly different.

B frames saves good amount of bits, but are more complex for decoder too. Qpixel makes it even harder.

Look i know we talk about portable players, but even on my one core CPU, xvid takes less power to decode than mpeg2 in HD (1080p). And the latter need much more bitrate to retain quality. Maybe its a matter of optimization though..


Im not insisting on anything. Just putting my 2 cents.


PS. What about theora on arm?

[saratoga]

Im not insisting on anything. Just putting my 2 cents.

Well if you're convinced that theres some point or advantage to this for your needs, then get to work porting a decoder and see how well it works.

[sirdan]

OMG sure... if i knew how to code eh