Analogue capture using DV codec

[bb]

Hi folks,

here are some interesting news from my most recent capture tests:

I captured a small clip (just one minute) using the Huffyuv codec:
- WinTV PCI
- Hauppauge's VfW drivers
- RGB colorspace
- 720x576

Then I filtered it using Telecide to get a progressive source, which I saved through Huffyuv again. So far everything's lossless, and you have the typical noise in the video which makes encoding harder.

Then I loaded this progressive Huffyuv file, and saved it
a) using PicVideo MJPEG at quality 19
b) using Panasonic DV codec

The file sizes from a) and b) didn't differ by much, but of course the Huffyuv file was much bigger. Comparing the three files regarding the noise, the DV file turned out to be the best, then Huffyuv, then MJPEG!

That was a surprise, so I decided to DivX encode the three files:
- DivX 5.0.2
- no b-frames, no q-pel, no GMC
- 1-pass at quantizer 2
- no pre-processing, no resizing, no psycho, etc.

As expected, the file from the MJPEG source turned out to be bigger than the Huffyuv original, because the JPEG compression is sensitive to noise. Thus it was bigger than the DivX file which was encoded from the Huffyuv source. The big surprise was the file created from the DV source: it was even smaller than the one created from Huffyuv source. This sounds a little strange to me, because DV uses a compression being similar to JPEG to a certain extent (DCT etc.).

Conclusion: regarding capture quality it seems that we get the following ranking (1 best, 3 worst):
1. DV
2. Huffyuv
3. MJPEG

I will further investigate on this and report my results. I may very well switch from MJPEG to DV for TV captures, if there are no other quirks I don't see yet.

But be aware of the following constraints when using DV for captures:
- You have to capture in RGB
- Resolution is fixed at 720x576 (for PAL, NTSC is 720x480)
- CPU demands are higher than for MJPEG

Any comments?


bb

[^^-+I4004+-^^]

>Any comments?


_few threads lower you'll find that someone
did it few days ago.....

probably DV IS BETTER ( probably because of DCT look-up tables that
are variable,not fixed as with (m)jpeg,but then again you're the expert on DV........)

for us with slower machines i guess it's out of question....

also...it's not that easy to:
1-spare enough place to capture to huff
2-spare some more to convert that to DV at cca. 5MB/s

(but for people with fast CPU's and bigger disks,i say->go ahead!)


and about noise?hmmm.....i like my video as sharp as it can get...
so it seems like DV is not so good choice for that.....
(i think for best quality huff->(end-format of choice))
less noise ALWAYS means less detail too,so i don't like it...
(i put sharpness to first place....also have you read stuff
by poptones and sansgrip on adding(!) noise?
it's really true that leaving some noise will produce sharper image.....)

cheers_

Ivo

[bb]

Originally posted by ^^-+I4004+-^^
also...it's not that easy to:
1-spare enough place to capture to huff
2-spare some more to convert that to DV at cca. 5MB/s

Hi Ivo,

just wanted to clarify that normally I do not capture to Huffyuv first and then convert to DV, but capture to DV directly. The intermediate Huffyuv step was for testing purposes only (to have identical source material for all codecs).

bb

[cjv]

I plan to try using the DV codec today...thanks for the idea!

cjv

[Malow]

i´m using a dv codec to capture for a month, and do doubt about quality compared whit mjpeg, a belive who have a power processor is the best way. look my tread:

http://forum.doom9.org/showthread.php?s=&threadid=39645

Malow

[symonjfox]

And what about MJPEG 2000 codec? I tried it in LOSSLESS mode, but with my Athlon XP 1700+, 512 MB DDR and hard disk ata 100, @ 352*288 25 fps ... I lose lots of frames.

Its compression should be stronger than HFFYUV in lossless mode, while in lossy mode it's really better than MJPEG (but still too heavy for today processors).

TEST:

I captured and encoded from my Hauppage WinTV GO a small clip in RAW YUV2 format (253*288 @ 25 fps) and WAV audio.

I reencoded it into HFFYUV (using Predict median and Convert to YUV 2 settings) without any audio track.

Final file size = 336 MB (encoding was very fast)

I reencoded the original file with Morgan MJPEG 2000 and these settings: Compression irreversible, Levels 5 Layers 1, 4:2:2 compression lossless and forced quality to 100%. No audio.

Final file size = 199 MB (encoding speed: 20 - 24 fps using Fast recompress option in VDub). I think that maybe next processors (like Athlon 64 or next P4) will be able to real time capture with this codec. I don't know why but the file was turned upside-down. Is it the codec or I wrong something?
-------------------------------------
Then I recompressed them in DIVX 5, no preprocessing, cropping, psycho, gmc, bframes or other. Just constant quantizer 2.

Transcoding HFFYUV was fast 50 fps in fast recompress mode (more or less).
Final file size = 45.6 MB

Transcoding MJPEG 2000 was slow: 25 - 30 fps in fast recompress mode.
Final file size = 45.6 MB

Conclusion: the 2 codecs are both REALLY Lossless, but Mjpeg 2000 is too heavy with my system.

[^^-+I4004+-^^]

>And what about MJPEG 2000 codec? I tried it in LOSSLESS mode, but with my Athlon XP 1700+, 512 MB DDR and hard disk ata 100, @ 352*288 25 fps ... I lose lots of frames.


and let me tell you what tyou already know:352x288
is lo res,so let's wait for P5 on 6Ghz for that!
(hehehe)

i tried it too and it's too demanding,but perhaps it could be used
as end format.....i didn't tested it that much though....
and i wonder if wavelet would play ok on my system even on lores(?)

[symonjfox]

You're right, but it's a new format, It has to be optimized and improved ... maybe next relases will be faster ;)

Let's wait ...