|
|
| dizzy23nc |
| Posted: Jan 19 2003, 07:18 PM |
 |
|
Unregistered
|
When objects or people move during yhe movie, lines and/or little blocks appear distorting the object. what causes this and what can I do to fix it? |
|
| jcsston |
| Posted: Jan 19 2003, 07:25 PM |
|
|
Matroska Dev
Group: Moderators
Posts: 553
Member No.: 652
Joined: 3-November 02
|
when lines or combing appear they are normally interlace lines. Try applying an deinterlace filter to the video. I'm using Deinterlace MAP right now
--------------------
Use the Matroska file format |
|
| Morsa |
| Posted: Jan 19 2003, 10:49 PM |
|
|
Moderator of the Vdub support board
Group: Moderators
Posts: 640
Member No.: 246
Joined: 9-September 02
|
For the blocks there aren't many solutions.
Where are you capturing from? DTV,VCD, DVD,etc. |
|
| Kippesoep |
| Posted: Feb 1 2003, 08:30 PM |
|
|
Moderator of the Virtualdub support forum
Group: Moderators
Posts: 447
Member No.: 441
Joined: 6-October 02
|
Just to explain the blocks: they are caused by a DCT based compression algorithm (such as MJPEG, MPEG1/2/4 etc). These break up the image into blocks (called macroblocks). If there's enough bitrate available and not a lot of motion going on, the iamge will be compressed with good quality. If the available bitrate isn't sufficient, compression will need to discard more information and lower the quality, which shows as blocks. This can also happen if there is a lot of movement. That will result in a larger difference between frames, therefore requiring more bitrate to compress or the compressor getting "confused" and not doing the motion estimation as well as is theoretically possible. Again, quality suffers.
If this is in your own encodes, you can alleviate the symptoms by either increasing the bitrate or through noise reduction (which means the compressor doesn't need to spend as much bitrate on compressing noise and more on the actual image).
If the blocks are in the source material, there isn't too much you can do about this, although there are some deblocking filters. One thing that can actually help in this case is add noise and then run a noise reduction filter. |
|
| dizzy23nc |
| Posted: Feb 3 2003, 03:20 AM |
|
|
Unregistered
|
what can I use for noise reduction? |
|
| Kippesoep |
| Posted: Feb 3 2003, 04:54 AM |
|
|
Moderator of the Virtualdub support forum
Group: Moderators
Posts: 447
Member No.: 441
Joined: 6-October 02
|
I have written two filters called "Dynamic Noise Reduction" and "Static Noise Reduction". You can find them on my website. I would recommend DNR at setting 8 followed by SNR at setting 6.
For more featured (but slower) filters which do pretty much the same thing, look for Jim Casaburi's "Temporal Cleaner" and "2D Cleaner" |
|
