Canon Xl-2????

[Andrew Kiu]

I planning to get one XL-1s, Anyone tell me when Canon release the next Version of XL-1s or XL2?????

[Aaron Koolen]

Hi Andrew. Do a search and you'll find this question popping up a bit - with opinions from many of the knowledgeable people on this forum.

Cheers
Aaron

[Adrian Douglas]

Andrew, it most likely won't be until next summer.

[Nathan Gifford]

Anybody that really does know has probably signed a NDA. Is that correct Chris?

[Chris Hurd]

Heh. I signed an NDA, but I really don't know... really!

Of course there will be something to succeed the XL1S, but most likely it won't happen until next year.

[Nathan Gifford]

Yeah, I think that is a pretty safe bet. One thing I wonder about is if the new system uses HD might it be MPEG? After reading some info on editing MPEG, I can see that might be a problem for standard NLEs.

[Peter Moore]

I still say an HD cam should use a DV-style intra-frame only compression. 1280 x 720 is a little less than 3 times the resolution of DV. So use 90-minute DV tapes for 33-minute HD clips and you're set. Cheap and simple.

PS - A 24p HD cam, 1280x720x24p, should also use 20% less of the tape than at 30p, something the DVX100 doesn't do.

I hope Canon and the other co's are listening. :)

[Kai Leibrandt]

Peter,

this is assuming the MPEG2 stream will have the same bandwidth as the standard DV stream, which is 25MBit/s. Most DVD's have bandwidths of under 10Mbit/s, so if you want the same quality it will be difficult if you don't increase the bandwidth of the final MPEG2 stream over 25Mbit/s...
However, as we can see from the offerings on the market that do MPEG2 on DV media, it is certainly possible, and I am certainly waiting to see what the first prosumer HD camera with removable lenses will be...

Kai.

[Peter Moore]

No, I'm talking about using DV intra-frame compression on HD, just at a higher resolution. Because 720/30p HD has a resolution of about 3 times DV, a 90 minute DV tape would be able to store 30 minutes of HD (perfectly acceptable), with no inter-frame compression, making it easily edited.

[Rob Lohman]

720p is less then two times the resolution of DV. DV has a
resolution of 480p [if your camera can do true progressive
capture].

[Peter Moore]

720 x 480 x 30 = 10368000
1280 x 720 x 30 = 27648000

Multiple = 2.67. In DV compression format, 720p would take up 2.67x the space that DV would, or 34 minutes per LP tape for 30p, or 42 minutes for 24p HD. That would make the most sense for pro-sumer HD capture and editing.

[Kai Leibrandt]

Unfortunately, DV holds no possibility for capturing in formats other than NTSC or PAL, so a different compression algorithm is needed, hence the use of MPEG2 over DV. This is no disadvantage however; even though DV is compressed at roughly 5:1, many MPEG2 codecs show better results in terms of artifacts etc than DV at higher compression ratios. Also we may finally be released from 4:1:1 or 4:2:0 in favor of 4:2:2, but this will depend on implementation... It is unlikely that higher res formats (like 720p etc) will be able to be captured using the 25Mbit max at 4:2:2 at an acceptable compression ratio... If anyone has any info on how the current crop of HDV capture, please let us now.

Kai.

[Peter Moore]

"DV holds no possibility for capturing in formats other than NTSC or PAL, so a different compression algorithm is needed,"

Please explain how this could possibly be so. I see no reason, technoloically (and I am a programmer among other things) why the intra-frame compression algorithm would not work at a higher resolution. The fact that DV works equally well for PAL and NTSC shows that it is not dependent on resolution.

And the enormous disadvantage of using MPEG2 is inter-frame compression, which makes frame-accurate editing extremely tedious.

[Kai Leibrandt]

Sorry for not being completely clear; it is simply a matter of standards. The DV format uses JPEG compression, and only allows for those two resolutions _as per the standard_. Of course, if you look at the specs of the standard, one quickly notices how the stream is actually split up into data blocks and control blocks, which is what things like dvbackup (with which you can use your DV cam as a streamer for backing up your computers data) use to write arbitrary data to the DV tape.

The same principle is used on the current crop of HDV cams, so the use the DV standard in a very loosely interpreted way, and write a non-DV video stream (MPEG2) to a DV medium. Of course, if you wanted to, you could also write full HD res material to the DV tape this way, you just wouldn't be able to do it in real time, as the DV tape mechanisms in cameras will only write 25Mbit/s, or roughly 3.5 Mbyte/s (including sound), to the tape (no more, and no less).

So basically you dealing with a situation that yes, you can write any kind of data to a DV tape, but as soon as it's not a DV video stream, it's not standard, which means you can't read it using a normal DV deck/cam. It also means that your bandwidth is limited to 25mbit/s for sound and video, how you split this up is up to whoever develops this non-standard device, but you will therefore have a maximum of 25mbit/s available for your video stream (if you don't record sound), but that is apparently good enough for 720p or 1080i mpeg2.

Kai.

[Rob Lohman]

I forgot about the horizontal increase as well... My bad, should
get some more sleep this week. Ehehe.

Anyways, Kai is correct. The STANDARD doesn't allow for anything
else. In theory you could go unlimited with DV compression
algorithm, ofcourse.

What currently is done is that an MPEG2 stream is written inside
the DV structure. Ofcourse devices that don't understand such
a construct (which isn't standard yet) would not read the stream