What Compressibility Check % do you settle for ?

[iparout]

Hi.

I was wondering, which % Compressibility check ratio is the lowest you are ok with ?

I am using DivX 5.02 Pro with GMC and B-Frames enabled and 128 kbps MP3 VBR audio and I like my movies to yield at least 45% in compressibility check.

[ArdenDag]

It depends on the circumstances.

I have to settle for 35-45% on 1 CD (700 MB) rips often, but if it's for my own personal use, I won't settle for less than 60-80%

[ReTroAcTive]

i like atleast 60% on a 1 cd rip and any where from 70% to 90% for 2. but ive found myself encoding at 50% when i have to, to get it to fit on 1 disc.

also,
i use vbr mp3s for sound , i like to use 160 as a rule but have used 128 when needs be.

[ReTroAcTive]

after your test has run you get a % , but that % will be higher if your going to go for mp3 sound from ac3. when you run your test it calculates your bits/pixel with ac3 audio file. on this movie im worken on now, Half Baked, after my test it said i was going to get 731 kbits/second or 0.327 bits/pixel for video. however after i run be sweet and transcode ac3 to mp3 my bit rate was boosted to 1051 kbits/second and after my credits where encoded at 20% my bit rate went up to 1100 kbits/second. im sure this brings the % up quite a bit.
so the % you get after your test is not always the % the movie is encoded at.
am i wrong?

[ArdenDag]

I thought GKnot took this into account when you filled the correct audio field.

[ReTroAcTive]

gknot takes into account the overhead for the vbr mp3 but the audio a file is still seen as an ac3 file unless you transcode the ac3 to mp3 before gknot calculates the file size.
as it did with half baked , when i selected the ac3 file for sound it says the audio will take up 269mbs , after i transcode with besweet the mp3 audio file is down to 77mb(vbr 128).
so, the bit/second for the movie went from 731 kbits/second to 1051, after the audio was transcoded to mp3, then to 1100 after the credits where encoded at 20%.
am i wrong?

[ArdenDag]

in GKnot, under Bitrate, I select Audio, MP3, 128 kbps before I do a compress check. That takes that percentage of the audio (17% I think) and 'saves' that much of the final file size for the audio. GKnot should already take that into account, if I'm not mistaken. Unless you forget to check that, and just check the overhead for vbr-mp3 (which is only 1%)

[TheWEF]

Originally posted by ReTroAcTive
so the % you get after your test is not always the % the movie is encoded at.

just don't "select" the ac3-file in the calculator if you're not planing to "just mux" but set the "bitrate" you are going to use for mp3.

there is no way to predict the filesize of credits so - yes, usually encoding credits separately will increase the percentage.

wef.

[ReTroAcTive]

i just seen that you can chose the bit rate to set the audio size , and all this time i was just selecting the ac3 audio file.
thank you

[OvERaCiD23]

I was wondering, which % Compressibility check ratio is the lowest you are ok with?

I'm a quality freak, so I shoot for above 70% on 2 CDs (10 cents for the CDs, why not?). I usually put 5.1 AC3 as well, so 70% is the common figure for my comptests (this is using Lanczos most of the time @ 640xXXX or higher). It all depends though, I don't go below 60% ~~> if the comptest is that low, I will go with 2.0 AC3 or 192kbps MP3.


I am using DivX 5.02 Pro with GMC and B-Frames enabled and 128 kbps MP3 VBR audio and I like my movies to yield at least 45% in compressibility check.

you'll be better off w/o using GMC. it doesn't aid compression, introduces artifacts, makes panning scenes jerky, increases encoding time, and increases CPU load for playback. basically, worthless IMHO. search around the DivX5 forum for more feedback on it, but the general consensus is that b-frames is the only really useful Pro feature.

you can use filters in AviSynth to aid your compression as well. Convolution3d is the best IMO, and can increase comptest results by up to 10% without blurring too much! be sure to use reasonable resolutions as well (for 1 CD, ~512-592xXXX is acceptable). it's much better to have a lower resolution video with no artifacts than a high resolution video with lots of artifacts ~~~> macroblocks!! :mad: ).

also, for audio, maybe read up on OGG Vorbis. you can obtain better quality sound @ 96kbps, and is the favorite among many of the people who go for 1 CD rips (which is what it sounds like you're doing with a 45% comptest threshold).

[N_F]

I usually try to stay in 60-70%. But just like Retroactive I sometimes find myself in ~55% (damn fullscreen movies...) just to fit it on one CD.

[codename_46]

I personally like to stick to 60% or better. I tried encoding 1 at 30% just to see what I would get......
well...... lets just say I would have rather donated the CPU time to SETI after seeing the results :D

[JohnMK]

At least 59%, no more than 70%. Otherwise, the resulting file may be undersized.

[ReTroAcTive]

i just finished encoding star wars ep1 to 1 cd at 544 x 224. the check told me the quality was at about 44% so i figured ide try it out and see what it would look like. ide like to say , i am very, very unhappy with it. i deleted it as soon as i seen what it looked like at full screen. im going to drop the rez and encode it again and i will never encode under 50% again.

[N_F]

Is Starwars ep. 1 really that hard to compress? If you get that low percentage at such a low resolution you're likely better of using two CDs.

[ReTroAcTive]

i want a 1 cd version of it also. i have a 2 cd version already that im very happy with.

[JohnMK]

I guage whether or not to go to 2 CDs based upon what % I get for 480H. If It's below 59%, I go to 2 CDs.