Capabilities of the hardware mpeg4 decoder.

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nullstring
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Joined: Fri Dec 14, 2007 6:58 pm

Capabilities of the hardware mpeg4 decoder.

Post by nullstring »

Recently I realized that the psp is capable of decoding 480p h.264...

Today, after doing a few searches around these forums, I found this thread:
http://forums.ps2dev.org/viewtopic.php? ... hlight=264

It seems to suggest that we can decode mpeg4 part 2.


I was just wondering if someone could please give me a summary of what exactly we can do this decoder and what we might be able to do in the future.

what I would like to do (and everyone else I am sure) is decode everything that is floating around on the tubes these days. Essentially, decoding of files containing xvid and x264 without being picky about it.


I was hoping that I would be able to play h.264 or XviD 480p video of resolutions 856x480 and 640x480 at full speed.

Is this possible? Will it ever be possible?

Thanks
Shapyi
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Post by Shapyi »

Well right now cooleyes and others have only been able to decode 480x272 res H.264 and MPEG4 videos with PSP in homebrew. But you are correct, in the XMB you can play 720x480p videos without a problem. Hopefully someone will figure out how to perform the same task in homebrew.

It would be great to have a media player that allows me to drag and drop my standard def AVI and MKV files to PSP for smooth playback without any extra encoding.
iam
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Post by iam »

Shapyi wrote:Well right now cooleyes and others have only been able to decode 480x272 res H.264 and MPEG4 videos with PSP in homebrew. But you are correct, in the XMB you can play 720x480p videos without a problem. Hopefully someone will figure out how to perform the same task in homebrew.

It would be great to have a media player that allows me to drag and drop my standard def AVI and MKV files to PSP for smooth playback without any extra encoding.
I'm pretty sure the PSP doesn't have the guts to run MKVs (at least not the standard 720p ones)...
I sure hope a good media player makes it sometime though, avi, wmv container is what I'm looking for...
J.F.
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Post by J.F. »

iam wrote:
Shapyi wrote:Well right now cooleyes and others have only been able to decode 480x272 res H.264 and MPEG4 videos with PSP in homebrew. But you are correct, in the XMB you can play 720x480p videos without a problem. Hopefully someone will figure out how to perform the same task in homebrew.

It would be great to have a media player that allows me to drag and drop my standard def AVI and MKV files to PSP for smooth playback without any extra encoding.
I'm pretty sure the PSP doesn't have the guts to run MKVs (at least not the standard 720p ones)...
I sure hope a good media player makes it sometime though, avi, wmv container is what I'm looking for...
Well, if it could be figured out how to make the codec decode more resolutions, it would be possible to make a player that decoded MKV/et al and re-muxed the streams as mp4. That would take almost no power at all. The power would be used to decode just the audio while the video was passed along (if the audio was aac, it could be passed along as well).
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Torch
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Post by Torch »

If you can identify the internal working of the scevideoopen (or whatever) function you wouldn't need to remux at all. Its highly probably that that function is just handling the MP4 container.

Most MKVs are AAC 5.1 anyway cos they are BD/HDDVD rips, unless they chose the less efficient original alternate DTS/AC3 stream to save them the headache of transcoding the HD audio as well.
J.F.
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Post by J.F. »

Torch wrote:If you can identify the internal working of the scevideoopen (or whatever) function you wouldn't need to remux at all. Its highly probably that that function is just handling the MP4 container.
Yeah, having one level further up would be useful, but more likely to be changed by Sony without warning.
Most MKVs are AAC 5.1 anyway cos they are BD/HDDVD rips, unless they chose the less efficient original alternate DTS/AC3 stream to save them the headache of transcoding the HD audio as well.
Many do, but many don't. Most of my MKVs have AC3 or OGG. But that's not a problem if the codec could be used for the video stream as that would leave plenty of power for decoding even DTS audio. The main CPU would split the incoming transport stream (AVI, MKV, OGM, MOV, etc) into the elementary streams, then remux the video into MP4 along with the audio if the audio stream is AAC. If not, the audio stream is passed to a decoder. The MP4 is passed to the codec.

That would be the "ideal" video player for the PSP. The only thing it relies on is that the elementary video stream is compliant with the Sony codec... and that's usually the case. In fact, like you mention, often the ONLY thing that the codec doesn't understand is the container.
Shapyi
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Post by Shapyi »

iam wrote:
Shapyi wrote:Well right now cooleyes and others have only been able to decode 480x272 res H.264 and MPEG4 videos with PSP in homebrew. But you are correct, in the XMB you can play 720x480p videos without a problem. Hopefully someone will figure out how to perform the same task in homebrew.

It would be great to have a media player that allows me to drag and drop my standard def AVI and MKV files to PSP for smooth playback without any extra encoding.
I'm pretty sure the PSP doesn't have the guts to run MKVs (at least not the standard 720p ones)...
I sure hope a good media player makes it sometime though, avi, wmv container is what I'm looking for...
Well I wouldn't expect 720p on PSP, but standard def should be possible.
J.F. wrote:Many do, but many don't. Most of my MKVs have AC3 or OGG. But that's not a problem if the codec could be used for the video stream as that would leave plenty of power for decoding even DTS audio. The main CPU would split the incoming transport stream (AVI, MKV, OGM, MOV, etc) into the elementary streams, then remux the video into MP4 along with the audio if the audio stream is AAC. If not, the audio stream is passed to a decoder. The MP4 is passed to the codec.
So there is no way for PSP just to decode a plain mpeg4/avc stream, it has to be in some sort of container?
J.F.
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Joined: Sun Feb 22, 2004 11:41 am

Post by J.F. »

Shapyi wrote:
J.F. wrote:Many do, but many don't. Most of my MKVs have AC3 or OGG. But that's not a problem if the codec could be used for the video stream as that would leave plenty of power for decoding even DTS audio. The main CPU would split the incoming transport stream (AVI, MKV, OGM, MOV, etc) into the elementary streams, then remux the video into MP4 along with the audio if the audio stream is AAC. If not, the audio stream is passed to a decoder. The MP4 is passed to the codec.
So there is no way for PSP just to decode a plain mpeg4/avc stream, it has to be in some sort of container?
There may be a way to avoid that, but I think what we have at the moment is container level.
Shapyi
Posts: 95
Joined: Mon Apr 25, 2005 9:31 am

Post by Shapyi »

J.F. wrote:
Shapyi wrote:
J.F. wrote:Many do, but many don't. Most of my MKVs have AC3 or OGG. But that's not a problem if the codec could be used for the video stream as that would leave plenty of power for decoding even DTS audio. The main CPU would split the incoming transport stream (AVI, MKV, OGM, MOV, etc) into the elementary streams, then remux the video into MP4 along with the audio if the audio stream is AAC. If not, the audio stream is passed to a decoder. The MP4 is passed to the codec.
So there is no way for PSP just to decode a plain mpeg4/avc stream, it has to be in some sort of container?
There may be a way to avoid that, but I think what we have at the moment is container level.
How is the decoder working right now? Are we using a PRX provided by Sony or has it been written from scratch? Because it might be a good idea to figure out how to access the different hardware syscalls and just write our own decoders from scratch that take advantage of the media engine hardware directly instead of going through Sony's.
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Torch
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Post by Torch »

Thats more or less way beyond the effort anyone is going to put into this.

The Sony PRXs reconfigure the VME and stuff I think, to decode in hardware. Its easier to just use their PRXs, although using them at one level higher that what we are now will be nice.
Shapyi
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Joined: Mon Apr 25, 2005 9:31 am

Post by Shapyi »

Do you know the specific prx modules that are being used? I might want to try disassembling them to get some insight into this.
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