is DV lossless?

[choirislife923]

i am just wondering....TechTV's "Guide to creating digital video like a pro" says DV is a lossless codec...is it? I'm a bit skeptical of that statement since there may be blockyness in DV video.

[D_Knife]

yeah... no
DV and "loseless" were first marketed as this compared to analogue video, in that you could transfer the footage from DV device to another DV device eg from camera to computer or camera to camera (if you wanted to) without any loss of quality, because the data is stored in a digital format this is just a simple file copy there are some other technical issues here but think in terms of file copy and your mostly on the right track - this is why people don't say capturing from DV - they say trasferring from DV, or they should anyway

DV is a lossy (ie it throws information away) format when altering the footage in some meaningful way, like using filters or titles or whatever. This is the bad news, the good news is that most DV codecs are fairly smart and take some steps to reduce re-compressing already compressed material again.
Some people have done generation test where they compress DV footage again and again on itself and see the results after a while it does get ugly but generally you can't see any real change until the 3rd or 4th generation

That said most people don't re-compress to DV again, they export straight to whatever they need eg MPEG 2, MPEG 1 or AVI for distribution

[D_Knife]

oh - forgot to mention you comment about the blockiness
Since DV runs at a fixed bitrate you can take footage of things that overload the DV codec and it has to resort to macroblocks
You are stuck with these, the best you can is keep them the same - at worst they will get worse
good luck!

[flaninacupboard]

highly saturated colours or lots of analogue noise looks bad on DV. things look like heavily compressed jpegs (which they basically are)

Now a cam with hardware huffyuv support would be cool 8)

[MpegEncoder]

Now a cam with hardware huffyuv support would be cool 8)

Except for the fact that you'd only get about 20 minutes of video on a one hour tape.

[choirislife923]

would DV be ok as a temporary format?

e.g.: i have a video in mpeg2 [3.9mbits], but after applying filters, i exported it into DV-avi (10 hours 35 mins....wow.....5 filters...color correction of overexposure...). what i am going to do with the avi is run it in tmpgenc to make an svcd compatible stream. i would do it with Vegas, but Vegas exports in 2520kbps SVCD...i need it around 1900kbps VBR (wont let me configure output). later on, i am going to convert it to DVD mpeg2 widescreen. would macroblocks pop up or would the video be ok?
in conclusion:
(1) mpeg2@3.9mbps VBR -> NTSC DV AVI -> mpeg2@1.9mbps SVCD
(2...when i get a dvd-r burner) mpeg2@3.9mbps VBR -> NTSC DV AVI -> mpeg2@8mbps DVD widescreen


note: its captured through a TV wonder & soundcard @ 352x240i...i dont know if widescreen works with 352x480i or not...if it does, then i'd do that for DVD instead of 720x480

[flaninacupboard]

why go from mpeg2->DV->mpeg2? just use TMPGenc and go straight from mpeg to mpeg...

352X480 doesn't support the 16:9 flag in DVD. you can however set the flag to 4:3, work out the size your image needs to be and then just set your TV to "wide" or "full"

[choirislife923]

why go from mpeg2->DV->mpeg2? just use TMPGenc and go straight from mpeg to mpeg...

editing video, adding titles, sound enhancement...etc...

[gratner]

why go from mpeg2->DV->mpeg2? just use TMPGenc and go straight from mpeg to mpeg...

editing video, adding titles, sound enhancement...etc...

You never never never want to go from a higly compressed format to a less compressed format and then back to the highly compressed format.

Use Womble MPEG Video Wizard to edit your MPEG-2 directly. It's a Godsend.

[BJ_M]

why not - its done all the time .. going from mpeg to dv or huffyuv , editing , and re-encoding ..


you cant do but basic editing in mpeg-vcr ...

straight white text on a black background also can look bad in DV -- but its a pretty good codec all around

the pal dv is better than the ntsc dv codec