why exactally cant a ds play standard mpegs

Discussion in 'NDS - Emulation and Homebrew' started by Findecanno, Apr 17, 2009.

Apr 17, 2009
  1. Findecanno
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    Member Findecanno GBAtemp Regular

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    I understand that the reason why there isn't a ds mpeg player is because you couldn't get enough fps from it but im wondering why that is. If a dpg is just an mpeg with a modified header and audio why can the ds handle that and not a straight up mpeg?
     
  2. m2pt5

    Member m2pt5 GBAtemp Fan

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    Standard MPG files are interleaved, which means the audio and video are stored alternately in the file to increase performance. The DS isn't powerful enough to read a file like this and maintain a good framerate, so DPG files are stored with all the audio in one chunk then all the video in another chunk. (Oversimplified, but sufficient for an answer.)
     
  3. DanTheManMS

    Member DanTheManMS aka Ricochet Otter

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    There was a guy working on a straight-up MPEG player, but he couldn't get it above 5 fps so he gave up on it.
     
  4. anoNL

    Newcomer anoNL Member

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  5. DanTheManMS

    Member DanTheManMS aka Ricochet Otter

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    That's not MPEG, that's XviD-encoded AVI with low-bitrate mp3 audio encoding. Still a good program though, especially for videos that refuse to stay in sync in DPG format no matter how you convert them (I use it for marching band videos, for instance).

    The one I was talking about was by ChuckStudios I believe, and never saw a release as far as I can remember.
     
  6. FAST6191

    Reporter FAST6191 Techromancer

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  7. anandjones

    Member anandjones GBAtemp Regular

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  8. saxamo

    Member saxamo Spaaaaace!

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    Just, No.
     
  9. DanTheManMS

    Member DanTheManMS aka Ricochet Otter

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    I've got it on my computer, and I assure you, it's not MPEG-based. A converter application on the PC turns the video into a series of bitmaps (stored in a folder called "bmps" no less) which are converted to a lower-filesize format and strung together into a *.nds file, basically turning the video into a glorified .gif animation. Open up http://danthemanms3.googlepages.com/video.ds.gba in no$gba for an example. If you open it in an emulator that can't keep up and runs the file slower than it should, you'll even see that it screws up the order of the frames because it uses the naming scheme of "frame1.bmp" "frame2.bmp" etc instead of "frame001.bmp" "frame002.bmp" so the frames get sorted wrong alphabetically when you have more than 9 frames in the video.

    I could package together the folder I've got and upload it if anyone's interested. Can't guarantee that the files won't be corrupted though, heh.
     
  10. Kingfield

    Member Kingfield GBAtemp Advanced Fan

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    Thats like asking why an ipod can't play AVIs
     
  11. Findecanno
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    Member Findecanno GBAtemp Regular

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    why cant an ipod play AVIs but a ds can but an ipod can play mpegs but a ds cant? that dont make any sense to me
     
  12. DanTheManMS

    Member DanTheManMS aka Ricochet Otter

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    An iPod won't play an MPEG you throw at it - it has to be converted to a format it can accept, with a certain range of acceptable resolutions and bitrates. Similarly, the DS can't just play any AVI file - you have to convert it to a specific resolution (256 pixels in width by whatever height you want), a specific video codec (XviD), and a specific audio codec (mono mp3 up to a certain bitrate).

    Point is, if you want a generic video player that can handle anything you throw at it, neither the iPod nor the DS is a good solution. A laptop or the upcoming Pandora would be a better option.
     
  13. fgghjjkll

    Member fgghjjkll GBATemp MegaMan

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    apparently there was another mpeg-4 player.
    it could play mpeg-4 with no sound and the video lags alot.
     
  14. FAST6191

    Reporter FAST6191 Techromancer

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    @fgghjjkll tuna vids and the unnamed project from abraxas (author of EZBuilder, an encoder up there or above batchDPG in my opinion) are the only two MPEG4 SP/ASP players I know of. Neither really represent a good option beyond proof of concept, personally I am stunned that it was even approaching possible.

    Still there are 7 odd videos methods I know of
    1 Moonshell DPG, the most common and probably the best method.
    2 Other format from Moonshell's author, I forget the name but the quality was pretty good and the filesize was enormous.
    3 Tuna vids- highly customised AVI files needed and at only 12fps or so it was not as smooth as DPG.
    4 Abraxas' project (also MPEG4 SP/ASP based)- even more proof of concept than Tuna vids. http://forum.gbadev.org/viewtopic.php?t=13951
    5 DSvideo- a wavelet based compression format http://dsvideo.recoil.org/ also stuck with low framerates and the need for a DLDI file compiled for the ARM7 (many were made though).
    6. The motion jpeg like format from birslip that DanTheManMS and I were speaking of a few posts up.
    7. In game formats, I have not tried custom insertion yet but it should work. I am including the format from the company that released a commercial format on the GBA but also as paid homebrew ( http://www.caimans.net/gbavideo/ )
     
  15. thedicemaster

    Member thedicemaster GBAtemp Addict

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    method 2, could that be DSM?
    1 of the 2 video formats natively supported by the m3real.
     

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