Target bitrate for 720p (From Blu-ray source)

[DrDeceit]

I currently use around 10 different encoders, and encode video frequently

I'll be using Adobe Media Encoder CS6 for future projects, due to its speed, and high quality

I want to convert 1080p Blu-ray sources into 720p

1,280x720
High Profile @4.1
2 Pass VBR
Maximum Bitrate 40.0 Mbps
Aspect ratio 16:9

I am having trouble figuring out what to use for target bitrate

I have many 720p videos from blursy sources anywhere from 4000kbps to 7000kbps

I simply want maximum quality, I don't want to choose 4Mbps if 6Mbps is better
But I don't want to choose 6Mbps if 4Mbps is exactly the same

Please note this is ONLY an h264 video stream, no audio, I mux my own streams

Help me out
(You may request my AIM address if you wish, I need more encoder-contacts anyways)

[jagabo]

6 Mb/s will always be better than 4 Mb/s. 10 Mb/s will be better 6 Mb/s. And 50 Mb/s will be even better. It's lossy encoding so the higher the bitrate the better the quality. The real question is where does the improvement in quality become so small that it's a waste. That depends on the particular video, the settings used, how closely you examine the video, and your particular tolerance for compression artifacts. There is no single bitrate that is "best" for all videos and all people.

I don't use Adobe Media Encoder CS6 but some encoders have a constant quality mode. You choose the quality you want and the encoder uses whatever bitrate is necessary for that quality.

[jman98]

Additionally if you are going to use bit rates around 4 to 6 Mbps as the original post says you may, it's really a bad idea to set the maximum bit rate to 40 Mbps. My advice would be to keep the maximum to not more than 2 times your average bit rate. If you are using a bit rate of 6 Mbps, for example, and part of the video does get encoded at 40 Mbps, to get down to your average of 6 Mbps you are going to have to some areas encoded at a really low bit rate so that that 40 Mbps area will stay within the average of 6 Mbps overall. Here's a rough idea.
40 Mbps section + 1 Mbps section = average of 20.5 Mbps, which is well above your average of 6 Mbps
40 Mbps + 1 Mbps + 1 Mbps + 1 Mbps + 1 Mbps + 1 Mbps + 1 Mbps + 1 Mbps = 5.88 Mbps average

So you see that we had to encode 7 sections in my mythical example at 1 Mbps to make up for the 1 section at 40 Mbps. This is just meant to illustrate the general principle. The higher your maximum bit rate value is above your average bit rate, the more you are going to have to encode BELOW the average bit rate to make up for the overage. And I don't want to mislead you and say that this will definitely happen, but if you are producing MP4 or MKV files there may be some secret limits on the maximum bit rates that standalone players will have (PCs won't care as long as the CPU is powerful enough to handle it). For re-encoding to other formats like MP4 or MKV, I'd suggest you really try to keep the maximum bit rate to 20 Mbps or less if you are going to be playing them on standalone players like media players or BluRay players.

[sparkyar]

7mbps average worked great for me, more than 8mbps was overkill and I couldnt spot the difference, and I always set the min and max parameters to
3mbps min
12mbps max

[deadrats]

for me, i would use 8mb/s for 720p or if you really want to get picky about it i would calculate the bit rate per pixel ratio of the source blu-ray and use that same ratio to calculate the bit rate for a 720p version. you can either do the calculation for the original yourself or you can ue mediainfo which will list it for you.

[deadrats]

I don't use Adobe Media Encoder CS6 but some encoders have a constant quality mode. You choose the quality you want and the encoder uses whatever bitrate is necessary for that quality.

can you explain something to me, why do people use constant quality or crf modes? as i look through various forums these modes seem to be picking up in popularity but i wonder why anyone trusts a piece of software to calculate quality for them. this is especially vexing since i've seen tons of encodes from various scene groups where they encode with something like crf 18 and everyone goes on and on about how great it looks and how it looks transparent to the source but when i download the video to check it out it looks like crap, there's macroblocking all over the place, in some parts there's over smoothing, they have to crank up the inloop deblocking strength to try and compensate.

so why do you, who from what i understand actually takes the time to write your own avisynth scripts for all your encodes turn around and leave the bit rate decision to the encoder?

[jagabo]

Because I don't have those problems. Many, many times I've compared CRF encodes to 2-pass bitrate encodes at the same average bitrate and they look essentially the same.

Are you using Intel's DXVA h.264 decoder? It's seriously screwed up.

[_Al_]

CRF is not a miracle alone, if somebody uses 2pass and tweaks settings, you have to do the same with CRF mode. Example, you have x264 settings for Blu-Ray on this web site http://www.x264bluray.com/ could be different command line, but I got it just handy here:

you migt use this line for progressive and 2pass:

x264 --bitrate XXXXX --preset default --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 30 --open-gop --slices 4 --fake-interlaced --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 1 --output out.264 input.avs

x264 --bitrate XXXXX --preset default --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 30 --open-gop --slices 4 --fake-interlaced --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --pass 2 --output out.264 input.avs

so this is 2pass and just other array of settings

so instead you can use this line (or set it within Megui, whatever good x264front):

x264 --crf 18.0--preset default --tune film --bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000 --level 4.1 --keyint 30 --open-gop --slices 4 --fake-interlaced --colorprim "bt709" --transfer "bt709" --colormatrix "bt709" --sar 1:1 --output out.264 input.avs

so you get same settings but only 1pass to get it and perhaps different bitrate, that's all, use of this line

x264 crf 18.0 --output out.264 input.avs

will not work even if I used "miracle" crf mode

Adobe Premiere and Sony Vegas use much simplified versions of Mainconcept encoder. It does not have Constant quality modes. MainConcept encoder Reference, where you can use Constant Quality, is sold separately.

Today most folks want to encode video and want to encode video so it looks good and to do it in "economic" way not to waste bitrate, every other question for encoding is like that.

[deadrats]

Are you using Intel's DXVA h.264 decoder? It's seriously screwed up.

nope, i'm currently using a quadro 600 and i use the built in decoders found in gom player, vlc and media player classic.

all i know is i've seen tons of encodes from scene groups that are very well known, HD music videos, some of those south american HDTV shows that basically amount to hot chicks with great asses wearing thongs dancing to music i can't stand, i saw a ghost rider 720p rip where the screenshots looked great and the file was 1.9gigs but when i downloaded it to check it out i deleted it inside of 2 minutes, what a mess of an encode.

just curious, but other than crf was settings do you use? do you use trellis, psy-rod, what sub me or do you just use a preset and call it a day?

[jagabo]

I usually work with DVD rips but here's a 720p sample I did a while back:

https://forum.videohelp.com/threads/348644-Overall-Bit-Rate-Bit-Rate-with-Respect-to-Qu...=1#post2187346

The CRF18 encode is about like I normally make. I keep the reference and bframes down for compatibility with a lot of devices. The others files were in the context of comparing 2-pass to CRF 25 where someone else suggested he saw big difference.

In general, I'm not looking to squeeze every last bit out of my encodings. Just to get decent results with a moderate file size. With CRF encoding I know what the final quality is going to be. I don't have to guess what bitrate a particular video is going to need.

[DrDeceit]

What about this

If I re-encode a video, with a higher bitrate than the original copy
The increased bitrate is all waste, because the bits were lost beforehand, they are simply not there RIGHT?

So, would the maximum quality cap of my 720p encode, be the same bits per pixel per frame as the source?

1080p - 14000kbps = 720p - 6222kbps ?

[jagabo]

If I re-encode a video, with a higher bitrate than the original copy
The increased bitrate is all waste, because the bits were lost beforehand, they are simply not there RIGHT?

Wrong. Lossy encoding not only reduces detail but produces artifacts. An encoder will see those artifacts as detail. It may reduce remaining detail from the original picture in order to retain some of the artifacts. You need to use a higher bitrate than the source if you don't want to lose additional detail and create more artifacts.

[Hoser Rob]

... other than crf was settings do you use? do you use trellis, psy-rod, what sub me or do you just use a preset and call it a day?

From what I've found those type of settings are the real meat in h.264 encoding. Without them I don't really see where h.264 is all that much better then xvid.

For example, in scenes that have things like rain or smoke or fog lit up against a dark background they make a huge difference. That stuff is a torture test.

Unfortunately that stuff is quite complex and I've never seen any way to really simplify them. With some software tasks you can just simply plug in numbers. With others you have to use judgement. And video encoding seems to be the latter type of process. I've looked high and low for something to simplify it. It doesn't exist.

For me the real benefit of h.264 crf vs 2 pass is that you can use those advanced settings ... which increase encoding time a lot ... without taking an insane amount of time to encode.

If you want to research advanced h.264 settings the best semi readable places I've found are the handbrake, mplayer, and avidemux doc sites. Bur bear in mind, those encoding options weren't designed for average computer users who just want to rip their video discs. They're professional standards.

[jagabo]

Of course, the presets adjust many of those settings for you. So beginners can use the advanced settings without knowing what they do. I made this table about a year ago (using MediaInfo to extract the settings from videos encoded with the presets):

ultrafast: cabac=0 / ref=1  / deblock=0:0:0 / analyse=0:0       / me=dia  / subme=0  / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0  / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0                                                                           / weightp=0 / keyint=250 / keyint_min=23 / scenecut=0  / intra_refresh=0                   / rc=crf / mbtree=0 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=0
superfast: cabac=1 / ref=1  / deblock=1:0:0 / analyse=0x3:0x3   / me=dia  / subme=1  / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0  / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3  / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0                   / rc=crf / mbtree=0 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00
veryfast:  cabac=1 / ref=1  / deblock=1:0:0 / analyse=0x3:0x113 / me=hex  / subme=2  / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0  / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3  / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=10 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
faster:    cabac=1 / ref=2  / deblock=1:0:0 / analyse=0x3:0x113 / me=hex  / subme=4  / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0  / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3  / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=20 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
fast:      cabac=1 / ref=2  / deblock=1:0:0 / analyse=0x3:0x113 / me=hex  / subme=6  / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3  / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=30 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
medium:    cabac=1 / ref=3  / deblock=1:0:0 / analyse=0x3:0x113 / me=hex  / subme=7  / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3  / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
slow:      cabac=1 / ref=5  / deblock=1:0:0 / analyse=0x3:0x113 / me=umh  / subme=8  / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3  / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
veryslow:  cabac=1 / ref=16 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh  / subme=10 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=8  / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00
placebo:   cabac=1 / ref=16 / deblock=1:0:0 / analyse=0x3:0x133 / me=tesa / subme=11 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=16 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40                 / aq=1:1.00

[DrDeceit]

Let me rephrase that

From 40Mbps h264 source, encode a 1080 and 720p version.
1080p = 14.0 Mbps, 720p = 6222 kbps

Same quality for their... resolutions?

Same artifact amounts for instance

KNOW WHAT I MEAN?

[jagabo]

Let me rephrase that

From 40Mbps h264 source, encode a 1080 and 720p version.
1080p = 14.0 Mbps, 720p = 6222 kbps

Same quality for their... resolutions?

Same artifact amounts for instance

Bitrate requirements don't scale directly with the number of pixels.