laserfan
6th November 2005, 20:44
I've been making Xvid files from my 1920x1080 ATSC HDTV transport stream captures and have struggled with lack of motion smoothness in the end results. I thought this might be due to "standalone support" not working (I make these Xvids for my Sigma-based ShowCenter players) but I believe now that it's something unrelated. Note I'm generally taking a 15Mbps 4.8Gb file and reducing it to a 350Mb file at 1100Kbps and something less than 720x480 e.g. 640x368 (that's up to AGK as I use two-pass mode). These tend to be 44min files.
When I look at the HD-to-SD logs of files that look jittery, I notice that "Source is considered to be hybrid" (not every capture is this way, some are deemed FILM, and for these they look smooth; no particular problems). After lots of reading here, I decide to try CTRL-F9 and "Force IVTC". Well, this output does not appear to have the twitchyness problem! Here's a log excerpt:
[10/27/2005 10:46:24 PM] Source has percentage of interlacing in motion areas: 40.61
[10/27/2005 10:46:24 PM] Source has percentage of telecined patterns: 90.50
[10/27/2005 10:46:24 PM] Source has percentage of progressive patterns: 3.46
[10/27/2005 10:46:24 PM] Source has percentage of interlaced patterns: 6.03
[10/27/2005 10:46:24 PM] Source is considered to be hybrid (mostly FILM).
[10/27/2005 10:46:24 PM] Looking for optimal hybrid thresholds.
[10/27/2005 10:50:36 PM] Found threshold of: 1.98
I have no idea why there are so many different patterns in these shows (this is from "Boston Legal"). Anyway if I leave AGK alone it does this:
Telecide(movie,order=1,guide=1,post=2).Decimate(mode=3,threshold=1.98)
The result looks very jittery in motion & pans. If I "Force IVTC" then AGK does this, and the result looks much, much better:
Telecide(movie,order=1,guide=1,post=2).Decimate(0)
OK so Decimate seems to be decimating my conversions (!), and "Force IVTC" seems to be the answer; but then I try one test for the heck of it with "Force Deinterlacing" and expect it to look horrible, and it does not!!??
This stuff is making my brain hurt; can anyone here who understands better than I these analysis results suggest how best to process them? Is Forcing IVTC the best compromise? I just need a pat on the head then.
Actually the smoothest result seems to come by converting the HD program to SD first by using a tool like HDTV2DVD and then AGK-ing the result, which is "pure Progressive" in nature. But this is a lot of extra messing around I'd rather not have to do.
When I look at the HD-to-SD logs of files that look jittery, I notice that "Source is considered to be hybrid" (not every capture is this way, some are deemed FILM, and for these they look smooth; no particular problems). After lots of reading here, I decide to try CTRL-F9 and "Force IVTC". Well, this output does not appear to have the twitchyness problem! Here's a log excerpt:
[10/27/2005 10:46:24 PM] Source has percentage of interlacing in motion areas: 40.61
[10/27/2005 10:46:24 PM] Source has percentage of telecined patterns: 90.50
[10/27/2005 10:46:24 PM] Source has percentage of progressive patterns: 3.46
[10/27/2005 10:46:24 PM] Source has percentage of interlaced patterns: 6.03
[10/27/2005 10:46:24 PM] Source is considered to be hybrid (mostly FILM).
[10/27/2005 10:46:24 PM] Looking for optimal hybrid thresholds.
[10/27/2005 10:50:36 PM] Found threshold of: 1.98
I have no idea why there are so many different patterns in these shows (this is from "Boston Legal"). Anyway if I leave AGK alone it does this:
Telecide(movie,order=1,guide=1,post=2).Decimate(mode=3,threshold=1.98)
The result looks very jittery in motion & pans. If I "Force IVTC" then AGK does this, and the result looks much, much better:
Telecide(movie,order=1,guide=1,post=2).Decimate(0)
OK so Decimate seems to be decimating my conversions (!), and "Force IVTC" seems to be the answer; but then I try one test for the heck of it with "Force Deinterlacing" and expect it to look horrible, and it does not!!??
This stuff is making my brain hurt; can anyone here who understands better than I these analysis results suggest how best to process them? Is Forcing IVTC the best compromise? I just need a pat on the head then.
Actually the smoothest result seems to come by converting the HD program to SD first by using a tool like HDTV2DVD and then AGK-ing the result, which is "pure Progressive" in nature. But this is a lot of extra messing around I'd rather not have to do.