acceptable fps for MVP

zehd · 2007-04-19, 03:48 AM

For a limited time, I have the files available on my FTP server

Just PM me and I'll provide the logon and password

zehd · 2007-04-19, 04:14 AM

Silly question alert...

Is the physical aspect ratio of a NTSC 4x3 screen the same as a PAL 4x3 screen? Is a PAL screen taller?

I know that PAL has more horizontal lines. Are they skinnier?

barakori · 2007-04-19, 04:17 PM

HtV Wrote:I tried this a few days ago, they all (23,97 , 29.97)play fine on my mvp, but as Martin explained: that's probably due to the fact that my tv automagically switches to ntsc mode when required. So I guess the mvp outputs them just as they are.

HtV, your TV may switch, but based on my tests, the MediaMVP doesn't. If it's set to PAL, it simply transcodes your 23.976 and 29.97 fps videos to PAL at 25 fps. You can check it - the temporary transcoded file is kept in C:\ and called MVP{long-number}.MPG - check its frame rate (using e.g. VirtualDubMpeg2).

See more in http://forums.nextpvr.com/showthread.php?t=25944

SuMo Wrote:As said, if you upload a small NTSC clip I'll try and see ...

I already mentioned I put some sample videos in http://www.xmixdrix.com/video/ they're relatively small - around 4MB each. You can try them out.

zhed Wrote:Is the physical aspect ratio of a NTSC 4x3 screen the same as a PAL 4x3 screen? Is a PAL screen taller?

The TV aspect ratio is 4:3 (unless it's a 16:9 TV, of course). TV aspect is different from frame aspect. Notice that in NTSC 720x480 has an "aspect" of 3:2, not 4:3. This means that NTSC pixels are a bit tall so that the 720x480 pixels will create a 4:3 image. In PAL 720x576 has an "aspect" of 5:4. This means that PAL pixels are a bit wide so that the 720x576 pixels create a 4:3 image.

BTW, a DVD resolution is 720x480 (in NTSC) both for 4:3 movies and 16:9 (widescreen) movies (Disclaimer: This is true for all but very few non-anamorphic DVD releases).

HtV · 2007-04-19, 05:16 PM

barakori Wrote:HtV, your TV may switch, but based on my tests, the MediaMVP doesn't. If it's set to PAL, it simply transcodes your 23.976 and 29.97 fps videos to PAL at 25 fps. You can check it - the temporary transcoded file is kept in C:\ and called MVP{long-number}.MPG - check its frame rate (using e.g. VirtualDubMpeg2).

Sorry if I was unclear about this: I made a few ntsc mpegs myself with ffmpeg. So I'm sure they were really 23.97/29.97 fps.
The mvp doesn't transcode, gbpvr/ffmpeg does that (on the fly). This is where the config-pal-setting is used (I think). So that if you have a pal(only) tv you won't have any problems playing "ntsc-avi's".

zehd · 2007-04-19, 07:58 PM

Yeah you know the more I think about it, I was chasing my tail.

If the video is transcoded to a PAL format MPG, and the MVP is set to PAL, and the TV is PAL, should be no problem.

As far as ZProcess though, it looks like I will have to adjust the match for maintaining the aspect ratio for PAL dimensions.

I may very well be taking a trip to Australia in the next couple of months. I will be bring my laptop and MVP to do some tests. But only for a day. I'm looking forward to seeing warm weather (even if it will be their Winter, it'll be a very sunny summer experience for me...)

HtV · 2007-04-19, 08:41 PM

This might be interesting: http://www.shspvr.com/smf/index.php?topic=5318.0

edit: and this one: http://www.shspvr.com/smf/index.php?topic=10627.0 you're in it. Smile

SuMo · 2007-04-19, 09:32 PM

barakori Wrote:In PAL 720x576 has an "aspect" of 5:4. This means that PAL pixels are a bit wide so that the 720x576 pixels create a 4:3 image.

...euhhh well actually not all of them..... I still deal with some 768x576 pixel formats (jobwise I mean) and these are 4:3 (square pixel format), these are analogue recordings like BetacamSP although the most (digital)recordings are in 720x576 (non square pixel) format.

zehd · 2007-04-20, 12:15 AM

HtV Wrote:This might be interesting: http://www.shspvr.com/smf/index.php?topic=5318.0

edit: and this one: http://www.shspvr.com/smf/index.php?topic=10627.0 you're in it.

hmmm

He didn't use caps, and he called ZProcess tedius....

zehd · 2007-04-20, 12:21 AM

SuMo Wrote:...euhhh well actually not all of them..... I still deal with some 768x576 pixel formats (jobwise I mean) and these are 4:3 (square pixel format), these are analogue recordings like BetacamSP although the most (digital)recordings are in 720x576 (non square pixel) format.

Yeah. I think it would be great if we divorce the two concepts: NTSC and PAL 4x3 Aspect ratios, and NTSC and PAL DVD dimensions.

Good to know that physically, the tubes are the same size, just fewer thicker lines of resolution with NTSC.

I hear that PAL can display pink too. I've always wondered when people talk about other people blushing on television, and yet we can't see it. Can PAL users see people blushing?

Just on these two points: more lines, and better colour, I wonder why the Americans went with NTSC back in the 50s...

barakori · 2007-04-20, 04:49 AM

barakori Wrote:HtV, your TV may switch, but based on my tests, the MediaMVP doesn't. If it's set to PAL, it simply transcodes your 23.976 and 29.97 fps videos to PAL at 25 fps.

Ooops, I meant GB-PVR transcodes (using FFMpeg), not the MediaMVP. Of course, the MediaMVP is only a playback device.