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Old 12th May 2011, 08:44   #181  |  Link
nm
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If like me you want to hit a precise result to fill your BD25 as much as possible, you can't avoid at least encoding twice your video...
Can't you mux audio with first pass video to check the overhead amount and then adjust second pass bitrate accordingly?
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Old 13th May 2011, 09:16   #182  |  Link
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No, beacause :
- My encodes are running most of the time while i'm not at home, and, i prefer to have optimal result, that target bitrate is exactly the same during 1st and 2nd pass.
- I've noticed, in practical use, "huge" differences between final bitrate of 1st and 2nd pass, most of the time bitrate of 1st pass is lower, wich make size of 1st pass unrealiable to adjust accordingly, when you want to fit at around 10MB for BR25 and 20MB for BD50.
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Old 13th May 2011, 10:19   #183  |  Link
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No, beacause :
- My encodes are running most of the time while i'm not at home
Write a script.

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and, i prefer to have optimal result, that target bitrate is exactly the same during 1st and 2nd pass.
That's really not necessary when you are only adjusting by some percents!

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- I've noticed, in practical use, "huge" differences between final bitrate of 1st and 2nd pass, most of the time bitrate of 1st pass is lower, wich make size of 1st pass unrealiable to adjust accordingly, when you want to fit at around 10MB for BR25 and 20MB for BD50.
I guess you could adjust ratetol.

But worrying about a 0.1 % undershoot is pretty insane anyway, IMO.
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Old 13th May 2011, 13:21   #184  |  Link
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Not at home, means : If i'm not home during 8h, and encoding take : 1h for 1st pass and 6h for 2nd pass, it will not change anything to stop after 1h or do the encode totaly, in both case, it will finish before my return.

But i'm insane, and using insane setting for encoding also.
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Old 13th May 2011, 17:31   #185  |  Link
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But i'm insane, and using insane setting for encoding also.
Ok, getting a dual-layer dvd movie that only uses 5gb is pretty crap. But seriously, .05%.

Encode something at 10000kbit/s, then the same material at 9950kbit/s. See is you can spot the difference. And that is .5%. 10x greater than what you are shooting for.
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Old 13th May 2011, 21:57   #186  |  Link
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Ok, getting a dual-layer dvd movie that only uses 5gb is pretty crap. But seriously, .05%.

Encode something at 10000kbit/s, then the same material at 9950kbit/s. See is you can spot the difference. And that is .5%. 10x greater than what you are shooting for.
Well, I'm more curious to know what sort of PC he has that he can encode a full movie at "insane" settings two passes in 8 hours. My i7-2600k at 4.2gHz with a full x64 flow takes about 12 hours for 2 passes at very slow.
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Old 14th May 2011, 03:20   #187  |  Link
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My i7-2600k at 4.2gHz with a full x64 flow takes about 12 hours for 2 passes at very slow.
Yeah, he does seem to be getting some good speeds for 'insane' settings.
Also, I don't encode 2 pass. But it is my understanding that there isn't a 6:1 ratio between passes either.
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Old 14th May 2011, 04:32   #188  |  Link
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Yeah, he does seem to be getting some good speeds for 'insane' settings.
Also, I don't encode 2 pass. But it is my understanding that there isn't a 6:1 ratio between passes either.
Unless you use --slow-firstpass the first pass is much faster than the second pass especially at the slower presets. On my system it's roughly 10:1. However, --placebo invokes --slow-firstpass which makes the first pass take as long as the second pass.

I guess we'll have to wait to see the command line he's using...
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Old 14th May 2011, 10:47   #189  |  Link
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would be nice if you could keep the whole "how to tune my command line" out of this thread,...

thanks
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Old 16th May 2011, 08:47   #190  |  Link
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I have an i7@980.
Don't have here my commande line, but i use placebo, and ajust a little the 1rst pass. Take me several tries to be sure to have the exact same numbers of I,B and P frame between passes and the overall parameters having globaly the same value. Speed ratio is around 4 between passes, and take around 24h for a 2h 1080p video, and 8h for a 720p video.

You can find my 1080p commande line here.
For 480p upscaled to 720p, it's the same but with level 4.0, 6 ref frames, 48 keyint, no slices and bitrate/buffer max at 15000.
All my workflow is also x64 (lossless codec x64 (UT Video) + Avisynth x64 + x264 x64).

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Old 16th June 2011, 22:39   #191  |  Link
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Hi guys, I'm trying to figure out the same thd overhead calculation, did you guys ended with some formula / tool for this ?
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Old 16th June 2011, 22:41   #192  |  Link
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nope, not enough statistical data to even think about a decent formula without knowing some basics about thd compression.
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Old 17th June 2011, 00:56   #193  |  Link
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Probably due partly to the fact that THD is pretty rare on Blu-Ray discs. DTS-MA is much much more common.
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Old 17th June 2011, 07:16   #194  |  Link
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+ no one knowns any specification
+ no reasonable priced encoder is available
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Old 17th June 2011, 08:04   #195  |  Link
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As i've said, i've put a rough estimation in post #156 here.
The few datas i've got give me the feeling that it may be impossible to have an very accurate estimation, because final size may be related too much to actual data. But it's only a guess.

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Old 18th July 2011, 03:02   #196  |  Link
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FWIW, I had a chance to play with Scenarist a little. It's m2ts files are slightly larger than tsMuxeR's. Like 20MB over a full "25GB" Blu-Ray.

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Old 18th July 2011, 05:50   #197  |  Link
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In general? With what content (steam types) ?
at the moment I roughly approximate the tsMuxeR Overhead by int(lengthInSeconds + 1) * 20.9 * 192 (byte) there might be a similar way to approximate the overhead Scenarist uses.
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Old 18th July 2011, 12:15   #198  |  Link
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In general? With what content (steam types) ?
at the moment I roughly approximate the tsMuxeR Overhead by int(lengthInSeconds + 1) * 20.9 * 192 (byte) there might be a similar way to approximate the overhead Scenarist uses.
Well, I only had a relatively short time to play with it, but on the 3 "movie only" discs I mux'd of AVC (H.264) + 5.1 DTS-MA (no subtitles) they were bigger.
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Old 20th July 2011, 08:25   #199  |  Link
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For information, all the datas i've provided were muxed with Scenarist.
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Old 20th July 2011, 08:27   #200  |  Link
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strange, the formulas did hold up when just leaving out the tsmuxerOverhead,..
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