#67089 - cncRaven - Sun Jan 15, 2006 12:54 pm
I'm about to get a SD card and i'm wondering what size do i need. I know what size are the games but i don't know about the video files? Iheard that there's a 90minute in 32 mb development, but i want to know what is the current situation.
#67123 - m2pt5 - Sun Jan 15, 2006 6:41 pm
The current format, DPG (played by Moonshell), is actually MPG video with (uncompressed?) audio. It has file size comparable to other MPG files encoded in the same resolution. (Actually quite small.)
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#67139 - JaJa - Sun Jan 15, 2006 8:54 pm
Audio is GSM compressed wav.
Size works out to be about 36mb for 21min with my settings of 256x192 @ 15 fps @ 180kbps.
Audio is encoded at 22050Hz
#67149 - tepples - Sun Jan 15, 2006 9:57 pm
Is MPEG-2 audio layer 2 significantly more computationally complex than GSM Full Rate audio?
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#67176 - JaJa - Mon Jan 16, 2006 1:09 am
| tepples wrote: |
| Is MPEG-2 audio layer 2 significantly more computationally complex than GSM Full Rate audio? |
I'd have thought so.
#67217 - tepples - Mon Jan 16, 2006 7:05 am
MP2 is the version of MPEG audio commonly used with MPEG movies, and I know it's a lot less complex than MP3. MP2 is a straight sub-band codec, not a cosine transform codec like MP3.
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-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.
#67236 - JaJa - Mon Jan 16, 2006 10:33 am
Yeah.
But I would still think it needs more CPU time to decode than GSM Wav.
Moonshell stuggles with Mpeg1 and GSM Wav.
I imagine Moonlight (the guy who made moonshell) has used GSM Wav for the simple reason that it is all the DS can handle with Mpeg1 video.
Why would we need Mpeg2 audio anyways?
#67284 - tepples - Mon Jan 16, 2006 6:45 pm
What is called "MPEG-2 audio layer #" is MPEG-1 audio at half sample rate. AAC (used most often with MPEG-4 and more rarely with MPEG-2) doesn't have numbered layers.
_________________
-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.
#67497 - brian33x51 - Wed Jan 18, 2006 5:22 pm
I've looked through the moonshell code.
His normal sound player stuff runs on the ARM9.
The video player does video decoding using the ARM9 and audio decoding using the ARM7.
If I ever get off my ass and get cracking with porting that nds emulator over to linux I'll start playing more with testing more formats on the ARM7. If I have time, that is.
Problem is the ARM7 is pretty anemic and likely would only be able to handle a single stream of ogg decoded data. But I can very seriously say the sound quality of gsm compared with ogg is like night and day.