cross dissolve noise

M

malmsteen

Active member
Hi all,

When I do a simple cross dissolve in FCP, I get slight noises during the dissolve.
It is OK most of the time, but sometimes, say 1 out of 10 dissolves do this.
Also, it "appears" to be OK in FCP editing interface though, but after exporting using compressor and authoring the DVD, it has noises.

Has anyone experienced the same problem before?
Any idea how to get around it?


Please help me out!
 
I've had a similar problem a few times. What I've done is raise the video bitrate to a higher average setting and make sure to encode audio to AC3 so I don't run into spatial issues. Is it always the same dissolve that is coming up noisy in the dvd file?
 
Yeah, actually it's always the same dissolve, I think..
Because I have so many dissolves, I can't quite tell if it's always the same one.
By the way, does it have anything to do with audio? why AC3 encoding?
Raising the bitrate doesn't seem to do much. Do you mean raise it in DVD studio pro or Compressor?
 
does it have anything to do with audio? why AC3 encoding?
Click to expand...
Because AC3 allows you to compress your audio much further(10 times or more) without a significant quality loss. So audio takes less space on the disc, lets say 125MB instead of a 1GB.Therefore you can compress your video with a higher bitrate, now that you have more space to spare.
Do you mean raise it in DVD studio pro or Compressor?
Click to expand...
He probably means in Compressor. You can use custom presets in Compressor instead of 60, 90,120 min presets. For example:
Lets say you have a 85min of video(plus audio) to make a dvd.
People often make the mistake of choosing "90 min High quality video" preset to fit it into a single DVD. If you look at the presets--->summary for that preset, you ll see Avarege bitrate for that is only 5mbps. You could create a new custom MPEG2 preset with 6Mbps, (and using using AC3 compression for the audio), you can easily get a DVD much better than the" 90 min preset".
Remember, more ecomplex the project and dissolves, you need to use higher bitrates and most importantly "2 PASS VBR BEST" MODE, under PRESET--->ENCODER--->QUALITY...
Also, in a problematic area you could put a compressor MARKER right on the dissolve area, which tells the compressor to be extra careful at that point.(Do not overuse)
 
Man...I didn't know and have always used 90 min preset.
I'm gonna try that and see how it works....sounds very convincing.

Thanks a lot for your help!
 
Malmsteen,
Let me also mention an important point when using the AC3(A-pack).
There are 3 tabs:
First tab is audio:
Unless you are making 5.1, choose 2/0(L,R) and put the data rate to 192,000kpbs.
Target system:DVD video
Change the dialog normalization to -31
Then click on the 3rd tab, preprocessing:
And choose "NONE" for compression preset. If you do not do this, your audio will badly flactuate throughout the video...
There you go, ;)
Btw, you can choose 6.7 mbps easily (even better than 6) for 85min video content if you follow the instructions above...
 
You must log in or register to reply here.
Back
Top