352 x 576 capture

[Chmod]

I must be missing something.

PCVCR offers 352x288 or 352x576 capture. The latter comes out looking all out of shape, which is obvious, considering the dimensions.

What is it for? Has anyone ever used it successfully to do anything useful?

Thanks,
David

[Damascus]

576 is a full field is it not? (288 * 2 = 576)

[paulw]

I think that 352 x 576 is a hang over from the old days when hard disks were small and expensive so you have the option of half frame capture to save disk space. From memory the Miro DC10 used this form of capture. These days it seems to be relegated to the history files.

[Dr Mordrid]

Actually the 352 wide half-frame sizes are VERY MUCH useful. In fact most satellite and cable providers use this format to transmit programs at a reduced bandwidth. This format is most often referred to as "half D1".

Another screen format option often used to reduce bandwidth is "2/3 D1", which is the 480x480/576 screen format used in SVCD's. The difference is that 2/3 D1 isn't limted in bitrate to the SVCD spec of 2600 kbps. 2/3 D1 is most often used by the DirecTV satellite service.

These formats, because they are based on a 704 wide frame, have a further advantage in that they are good for generating MEPG's at fractional frame sizes. Half or 2/3 of a 720 wide frame, as used in DV, is not useful for MPEG's since these sizes are not evenly divisible by MPEG's 16 pixel wide macroblocks. 704's half and 2/3 wide formats are evenly divisible by 16.

The reason half D1 can deliver good quality at half-width is because each color sample in a broadcast signal is spread across 2 horizontal pixels. As such you can drop one pixel/sample across the screens width and not lose any color information. 2/3 D1 isn't so neat in its application, but it's also using a wider frame so it too gives quite acceptable results.

Half D1 and 2/3 D1 only look out of proportion when displayed on a computer. Cards with good analog outputs re-scale them to full screen when they're sent to the video output. The Matrox DualHead cards DVDMAX feature can handle both formats in about any codec DirectShow can display.

If the display card in your editing workstation cannot do this than reconsider your options since these formats are VERY useful in keeping projects that don't need a lot of fancy effects down to a manageable size. I use them quite a bit myself.

Dr. Mordrid

[Rob100]

I would also add to Doc's statement, that this resolution is useful for capturing for encoding as a SVCD's as many DVD players (well those that play "standard" SVCD's) will play this resolution no problem.

[Chmod]

Okay.

I wish I had known a lot of this sooner.

My next question would be, is there any way of playing a 352x576 resolution file on a PC so that it looks normal?

My real issue is to do with really long captures. PCVCR seems to be the only way to access the MPEG2 encoder, that I'm aware of. As such, 352x576 is the best resolution available. It's just that it's really difficult to look at.

Any ideas?

Thanks,

David

[Flying dutchman]

I'd also like to add that if you encode the audio at 48 KHz, 352x576 is also a valid resolution for DVD encoding.

If your dvd player supports "miniDVD" (i.e. dvd data format on a cd-R) this is a very good archiving format for about 40 minutes/disk. You can always copy the data files to a "true" DVD/R as soon as these become affordable...

[dZeus]

to display avi & mpeg1/2 at any aspect ratio you want to, use sasami2k (www.sasami2k.com). With the PowerDVD 4 directshow filters it can also properly play back any mpeg1/svcd/vob file.

[Rob100]

I always use WinDVD to play MPEG2 files which are 352x576.

[Indiana]

Especially with interlaced material the 352x576 resolution will give much smoother playback and thus is superior to the 704x288 one (which has an equal data rate).
Any player that lets you force 4:3, 16:9 or even a custom aspect ratio should play the file correctly - PowerDivX NG or DivX' "The Playa" for example.