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compression artifacts
I’ve made a dvd of a 3 minute music clip and there is a few shots in the first 15 seconds that look particularly bad as far as ‘digital blocks’ are concerned. I’ve used a lot of filters and effects in the clip and there is some heavy effect stuff right from the bat. The artifacting is very apparent right from the beginning but because I’ve applied such heavy effects, it is acceptable because the viewer won’t notice it.
It becomes annoying in a shot of a man’s face while he’s dancing.
Can I improve that part by using compression markers? If so, how do I do that?
I used the 90 minute BEST preset in Compressor. It’s DV-PAL material. I tried upping the max bitrate to 8.5- nothing works…
There must be a way to make a 250 mb clip look better on a dvd that can hold 4 gigs of video…?
G5 Quad, 3.5 Gig RAM, OS 10.4.10, FCS 2
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6 Replies
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To lay down compression makers goto the areas in question in your sequence and place the play head on first frame of the shot that’s giving you the problem, make sure no clips are highlighed, then press m twice. A marker dialog box will come up, select compression marker. This will force an “i” frame at that spot.
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If you export from the FC time-line, you don’t need to set Compression Marks. FC set a CM for you whenever there is a cut, a transition or any other thing that would complicate the compression.
Lately I’m making MPG2 wit Short/Open GOPs and with the Peak bit-rate to 8.5Mbps.
Scenes with a lot of movement or transitions look great.
RafaelPPC G5 2x2Gh 4GbRAM/BlackMagic SD/PMBP 17″Core2Duo 4GbRAM
JVC DTV-17″/FCS2/AE CS3/COMBUSTION/SHAKE -
[Rafael Amador] “Lately I’m making MPG2 wit Short/Open GOPs and with the Peak bit-rate to 8.5Mbps.
Scenes with a lot of movement or transitions look great.”I tried setting the peak rate to 8.5- no difference. What’s with the Short/Open GOPs- you create your own? You manipulate them? Please explain.
G5 Quad, 3.5 Gig RAM, OS 10.4.10, FCS 2
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Hi,
If you want to make a good DVD, the first thing you need is a good movie. A good master.
You can never get a good master from a DV sequence. Mostly when, as you say, your movie have a lot of effects.
Instead of tweaking the MPG2 parameters in Compressor, go to your FC project. Duplicate your sequence and change the codex. Set 8b Uncompressed. Do not render. Send the sequence to Compressor and use the 90 minutes High Quality setup.
Please make a try like that. You will see how your MPG2 will look much better. Probably all the artifacts will disappear just like that. If this is not enough I will tell you a couple of things you can do. But please start as i tell you, just change the codex.
RafaelPPC G5 2x2Gh 4GbRAM/BlackMagic SD/PMBP 17″Core2Duo 4GbRAM
JVC DTV-17″/FCS2/AE CS3/COMBUSTION/SHAKE -
Followed your advice: duplicated the sequence and changed in the Sequence Settings-Compressor Settings to uncompressed 8-bit. Did not render but sent it straight to Compressor using 90 minute Best Quality.
I hate to say the blocks are still very much there… it seems there was an improvement but not dramatic.I also noticed the aspect ratio was 4×3 as opposed to the 16×9 in the output of the DV sequence.(?)
Appreciate your effort and am really interested to learn how you get good dvd’s from dv footage. (with a thick layer of effects&filters…)
G5 Quad, 3.5 Gig RAM, OS 10.4.10, FCS 2
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Great instructions so far… I pretty much understand the uncompressed workflow, which preserves quality across render- but do you also include adding the shift fields filter (i’m in pal, and SD pal is upper field dominant). Or does compressor interpret this part automatically? (i somehow don’t really trust final cut with fields).
The shift fields is something i need to really comprehend, as recently i had a project that had largely dv material, with some mixed media thrown in (dvcprohd, animation and sd footage), and thinking i could nest the project on mastering (it was a digital beta master) and work off a dv timeline, since most of the clips were dv. but what happened was that I got field tearing, when i changed my sequence to uncompressed, with or without the shift fields filter. (which is really strange, as i’ve used this workflow quite a few times, but without the mixed media).
Next, as most of my current projects are fairly short, I’m encoding dvds/mpg2s with this setting:
Gop Pattern: IP
Length: 6, open
vbr 6.6 to 7.5 mbs/dualpass encodingMost of the projects were initially shot on DV25, but i seem to be seeing artifacing as well as noise quite a lot. Okay, The shorter GOP length seems to be able to prevent blockiness around dark moving areas, and it seems to hold quite alright across dissolves… but areas where there are white text with a black shadow (program subtitles) seem to pixelate at the edge of the text (reminds me a little of an offline edit off the Avid). Any tips on improving the workflow?
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