Enabling DMA effecting avisynth

[xnakx]

is there any reason that enabling DMA on a hard drive would affect avisynth good or bad?




xnakx

[UGAthecat]

It should definitely affect it for the good, especially if you are working with a large filesize source, like uncompressed or huffyuv video. Probably wouldn't help so much with mpeg sources, but it shouldn't ever hurt to have dma enabled for your drives.

[theReal]

You shouldn't ever be running HD's in PIO mode because access to PIO mode devices costs you a lot of cpu power (about 50-100%...) and in addition to that, the transfer rate will be limited to about 16MB/s in PIO mode 4.

I guess everyone here using avisynth has DMA enabled for his IDE HD's, so you can be pretty sure there are no problems with it.

[xnakx]

well when i enable DMA for the DVD drive rip speeds are increased substantially, But when i enable it for the hard drive(IBM DeskStar 40g) I have read errors and execption errors with Avisynth. Disable it on the HD and things are all well agian. I guess i should take a look at the other components (RAM, MB)

thanks for the replies

[theReal]

Hmmm, maybe it can has some influence after all?
I've eventually experienced some random read errors for avi files with avisynth 1.06 and now again with 2.05. The error is (-379) "unable to decompress frame xxx" and it happens randomly, it doesn't have any connection with a certain frame, it is not due to a corrupt file (the error is not reproducable, on the next try the whole file works).

I just thought of switching back to 2.03 because it didn't seem to have any problems at all. I will certainly not disable DMA because of that error. Disabling DMA for HD's is not a solution in my opinion because it's too essential.
Also, this random read error has occured reading from an IDE RAID0 partition as well, a drive that is seen as a SCSI device by Windows, no chance to disable DMA here.
In addition to that, the errors only occured when feeding to Mediaplayer and Realproducer 9, never when feeding to VDub...

Can you try if you still get the errors with avisynth 2.03? I'll also switch back to 2.03.

[unplugged]

Originally posted by xnakx
well when i enable DMA for the DVD drive rip speeds are increased substantially, But when i enable it for the hard drive(IBM DeskStar 40g) I have read errors and execption errors with Avisynth. Disable it on the HD and things are all well agian. I guess i should take a look at the other components (RAM, MB)

thanks for the replies
Check your HD internal cables (must be Ultra-66/100/133) and attach your HD to the final connector (opposed to coloured connector), for the moment it seems that you are experiencing transfer corruption errors, your system is generally unstable (not avisynth).
PIO mode in Winodws controller properties limits your HD/system performance at all, in fact not more than ~5 Mb/s (with DMA on ~40 Mb/s)...
16 Mb/s is the bandwidth limit in case you select PIO mode4 in BIOS and then you enable DMA from Windows properties (in fact each HD mode has its DMA feature). As opposite when you find PIO mode selected in Windows controller properties the system is working in "POLL" mode (~5 Mb/s), this means that bytes are not transferred as small/large packets (DMA mode) but one by one :scared: or similar way (this justifies the very high CPU usage).

Check entire your hardware/software setup, every system MUST work with DMA enabled on HDs.

[xnakx]

as far as i can tell everything is DMA compatable. Ultra-66 cable(blue end connected to MB and the far connector to the hard drive). the MB is an asus (cusim), it is a combo board with sound and video on board, i am starting to think the board might be the problem.
this might be a stupid question but are the Ultra-xxx cable required for dvd or cdrom drives to operate in DMA mode. I am currently using the one that came with the drive(40 pin cable)?

[unplugged]

When CD units or similar don't go beyond UltraDMA-33 mode leave these with normal 40-pin cable, this last works perfectly.

[theReal]

For me, avisynth 2.03 seems to be the solution (no more random read errors up to now), so I guess it's some software thing. I don't mind anymore as long as v. 2.03 works flawlessly.

btw. I'm using UDMA 100 certified, twisted pair round cables for all my IDE devices and I have no problems with DMA (but the old 40-pin UDMA 33 cables are usually better if CDROMs are having problems with DMA).

[xnakx]

ok thanks for all the help