Eva files

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Par [D-Tail]

Ascended (8258)

Portrait de [D-Tail]

20-02-2006, 14:15

You say you have an MSX turboR. I say you try the /W and the /V command line options. Usually the /W takes care of the audio jitter. Smile

Par scratch_disk

Expert (72)

Portrait de scratch_disk

22-02-2006, 15:42

Thanks for the replay, though I couldn't have time to use my MSX and try the options.
Well, Amestrad CPC SymbOS has a video player www.symbos.de/files/videoplay.gif with a control panel (play/stop, forward/backward) while the EVA player has not? Can that be implemented in evaide.com?

Par ARTRAG

Enlighted (6828)

Portrait de ARTRAG

22-02-2006, 16:16

few questions...

Does the EVA player works on a pure z80 ?

Who does develop/mantain the EVA players for MSX?

Who knows how the audio of EVA files is encoded and played (what is the covox device I have seen)?

Par NYYRIKKI

Enlighted (5917)

Portrait de NYYRIKKI

22-02-2006, 16:21

(play/stop, forward/backward) while the EVA player has not? Can that be implemented in evaide.com?

There is no reason, why it could not be done. If you want to do that, EVAIDE sources can be found here.

Par scratch_disk

Expert (72)

Portrait de scratch_disk

22-02-2006, 16:47

There is no reason, why it could not be done. If you want to do that, EVAIDE sources can be found here.

Well, I'm just talking the talk, not walking the talk Tongue. It was just an idea that came into my mind when I saw that CPC Symbos.

Par Sonic_aka_T

Enlighted (4130)

Portrait de Sonic_aka_T

22-02-2006, 23:58

Does the EVA player works on a pure z80 ?It's 100% Z80 assembly if that's what you mean. It's also not specifically R800 if that's what you meant.
Who knows how the audio of EVA files is encoded and played (what is the covox device I have seen)?Audio is not encoded, it's just raw PCM data. It's played by just outputting the data to the respective port, which is either the tR PCM, Music Module or covox dac port. A covox is a simple parallel port DAC that is connected to the printer port. Just search for the word on the net, you'll see.

Par ARTRAG

Enlighted (6828)

Portrait de ARTRAG

23-02-2006, 00:07

So, if I modify audio section of the EVA encoder/decoder including the algorithms of PCMENC,
I could get on a z80@3.57MHz a full eva player that does PCM audio and straming video on MSX2...

Correct?

Par [D-Tail]

Ascended (8258)

Portrait de [D-Tail]

23-02-2006, 08:56

If that PCMENC can decode 15.75kHz sound in reasonable time, yes.

Par [D-Tail]

Ascended (8258)

Portrait de [D-Tail]

23-02-2006, 09:00

Before I forget though, MSX2 would really need V9990 for the video data, although you could convert your EVA files to downscale them to screen 8.

Par ARTRAG

Enlighted (6828)

Portrait de ARTRAG

23-02-2006, 11:36

Hi D-Tail
The re-player of pcmenc is very light, and can go to up to 44,1KHz with 3 bit LRE, without encoding could also rise the frequency rate (at about 70KHz), but at the cost of a huge waste of space (3bytes per sample @ 15KHz is a lot of space).
The problem is that "very light" couldn't be enough when you have to do video decoding at the same time.
How heavy is the video-decoding of Eva files? What is the encoding algorithm ?
How many Tcycles per frame are required ?

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