Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion. Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules. |
17th September 2008, 17:25 | #1 | Link |
Registered User
Join Date: Sep 2003
Posts: 80
|
Use Turbo mode?
What are the opinions as to how much improvement in quality is gained by turning turbo off in some of the presets (say unrestricted 2 pass HQ or unrestricted 2 pass EQ modes). Is it negligible or are there many of you that think turbo mode hurts quality enough that you don't use it?
|
17th September 2008, 17:31 | #4 | Link |
Mr. Sandman
Join Date: Sep 2003
Location: Haddonfield, IL
Posts: 11,768
|
i think he's talking about megui
__________________
MPEG-4 ASP Custom Matrices: EQM V1(old), EQM AutoGK Sharpmatrix (aka EQM V2), EQM V3HR (updated 01/10/2004), EQM V3LR, EQM V3ULR (updated 04/02/2005), EQM V3UHR (updated 17/12/2004) and EQM V3EHR (updated 05/10/2004) Info about my ASP matrices. MPEG-4 AVC Custom Matrices: EQM AVC-HR Info about my AVC matrices My x264 builds. Mooo!!! |
17th September 2008, 18:14 | #7 | Link | |
Registered User
Join Date: Nov 2003
Posts: 1,281
|
Quote:
And yes, that is Adapt. B-Frames setting. edit: with b-adapt 1, the speed gain is worth setting turbo mode. With b-adapt 2, that could be different depending on source. See here. http://forum.doom9.org/showthread.ph...74#post1184974 Then goto the start of that thread and read. Last edited by Audionut; 17th September 2008 at 18:17. |
|
17th September 2008, 20:00 | #9 | Link | |
Compiling Encoder
Join Date: Jan 2007
Posts: 1,348
|
Quote:
b-adapt is ignored on the 2nd pass. any change in settings from 1st pass to 2nd pass that would normally affect frame decisions on a 1st pass will not change the decisions at all. it uses the 1st pass .stats and does not change it. (why .stat hacking has worked for ages for specifying frame types on 2nd passes) so 'turbo'ing on the first pass will make the first pass go faster, but you get worse decisions to use in the 2nd pass. it's up to you if you desire this quality/time trade-off. Last edited by kemuri-_9; 17th September 2008 at 20:02. |
|
17th September 2008, 20:19 | #10 | Link |
Registered User
Join Date: Feb 2007
Location: ::1
Posts: 1,236
|
However, the changes are very, very minimal. Even when I use extreme (--me umh (maybe higher) --merange 32 --subme 7 --trellis 2 --no-fast-pskip, etc.) settings, I usually do "turbo" (fast first pass). If you have a very slow AVS script, though, and you don't want to do a lossless pass, then it may be worth it to do a higher quality first pass, since the encoding is mostly limited by the AVS.
|
17th September 2008, 20:27 | #11 | Link |
Compiling Encoder
Join Date: Jan 2007
Posts: 1,348
|
OK, so what are these 'turbo' settings that MeGUI has so i can compare them to the slower settings i use.
that is, all the settings... the default x264 ones, the default megui ones, and then the settings that the turbo mode specifies. |
17th September 2008, 20:32 | #12 | Link |
Registered User
Join Date: Feb 2007
Location: ::1
Posts: 1,236
|
Not sure what MeGUI's turbo is, but this is what I use:
x264.exe --bframes 3 --b-adapt 2 --b-pyramid --deblock -1:-1 --bitrate 6500 --pass 1 --stats "C:\Example.stats" --partitions none --direct auto --weightb --me dia --subme 2 --output NUL --level 3.2 --progress --threads auto "C:\Example.avs" So basically, deblock, bframes, weightb, b-adapt, b-pyramid, and direct (and AQ) matter. Everything else can be slaughtered. A possible idea for a test, also, is doing the first pass with worse AVS filters. This is more touchy, though. For example, with degraining, do the first pass and try to get the same amount of grain lost, just use fast filters even if they kill a good amount of detail. |
17th September 2008, 21:05 | #15 | Link |
Broadband Junkie
Join Date: Oct 2005
Posts: 1,859
|
MeGUI's 1st pass turbo mode is something like this but largely depends on what options are chosen (I haven't listed all options and possibilities):
--pass 1 --bitrate XXXX --bframes XX --b-pyramid (if set for pass 2) --b-adapt 1|2 --direct auto --filter X:X (set the same as pass 2) --subme 1 --partitions none --me dia --threads auto --thread-input --progress --no-dct-decimate (if set for pass 2) Kemuri, why not just download a build of MeGUI that you can fool around with? It shows you the x264 cli it uses when you change settings. Last edited by cyberbeing; 17th September 2008 at 21:14. |
17th September 2008, 22:00 | #16 | Link |
Turkey Machine
Join Date: Jan 2005
Location: Lowestoft, UK (but visit lots of places with bribes [beer])
Posts: 1,953
|
Wrong forum, for a start! MPEG-4 Encoder GUIs.
@mod: please move this.
__________________
On Discworld it is clearly recognized that million-to-one chances happen 9 times out of 10. If the hero did not overcome huge odds, what would be the point? Terry Pratchett - The Science Of Discworld |
17th September 2008, 23:31 | #18 | Link |
x264... Brilliant!
Join Date: Mar 2005
Location: Rockville, MD
Posts: 167
|
"Turbo Mode" may be a checkbox in a GUI, but the formation and usage discussions belongs here. People who do 2-pass by command line or batch file are benefited by this discussion. The only benefits for a GUI would be developers who want to tweak their turbo option or people who want to try to convince them to do so.
|
18th September 2008, 14:09 | #19 | Link |
Registered User
Join Date: Sep 2003
Posts: 80
|
I'd be happy to provide you with those details if I could figure out how to get them. Usually when you change a setting the command line changes in the interface, but when I click or unclick turbo I don't see where it changes so I don't know how to post the difference between turbo on and turbo off here so that I can get some opinions as to how that would affect the final encode. How the command line changes is probably a question I could post in the GUI forum.
|
18th September 2008, 15:49 | #20 | Link |
Registered User
Join Date: Sep 2006
Location: UK
Posts: 416
|
If you want to see what meGUI has done, look in the logs. Otherwise you can browse the source to see what it is doing, I think this is the section:
Code:
533 if (Turbo) 534 { 535 NbRefFrames = 1; 536 SubPelRefinement = 0; 537 METype = 0; // diamond search 538 I4x4mv = false; 539 P4x4mv = false; 540 I8x8mv = false; 541 P8x8mv = false; 542 B8x8mv = false; 543 AdaptiveDCT = false; 544 MixedRefs = false; 545 BRDO = false; 546 Trellis = false; 547 noFastPSkip = false; 548 WeightedBPrediction = false; 549 biME = false; 550 } |
Thread Tools | Search this Thread |
Display Modes | |
|
|