mkv/mp4 720/1080p birate info

[ckamc]

I am currently encoding a video and its taking longer than some of the others for my ps3. I was wondering what the average bitrate should be for a 720p and a 1080p video file. I looked at a few calculators but they are aimed at dvd's still.

I tried to use two seperate video info programs (one being gspot) but neither would register what the mkv or mp4 file produced as the average.

I looked at a view profile's in one video application and it has 8192, 4096, and 5120 as some of the popular average bitrates.

I set a 720p encode to 8192, would this be considered too high or just right?

before I used another application where I had the quantize matrix equal to 21 and produced the exact same quality(at least to my eyes) but with a smaller file size compared to the original, had to revert to another application because the video produced by the application that I have set to use a matrix came out extremely jumpy.

P.S. when I say smaller file size two of my video's went from 2.8 -> 2.0gb(720p @21) and 8.01gb -> 3.6gb(1080p @21)

Thanks for your time and help

[jagabo]

file size = bitrate * running time

This is always true, regardless of what codec you use.

If you don't need files of a specific size, like 700MB to fit on a CD or 4.3 GB to fit on a DVD, why don't you forget bitrates and encode with constant quality. You'll always get the quality you specify regardless of the frame size, frame rate, and nature of the video.

[poisondeathray]

FYI mediainfo > gspot for parsing information on MKV's

The average bitrate will vary for different types of movies. One with lots of detail and motion should have a higher bitrate than one with simpler scenery

To minimize wasting time, you can encode a sample representative clip (like 60 seconds) with various bitrates and see if it is acceptable to you

[jman98]

I set a 720p encode to 8192, would this be considered too high or just right?

before I used another application where I had the quantize matrix equal to 21 and produced the exact same quality(at least to my eyes) but with a smaller file size compared to the original, had to revert to another application because the video produced by the application that I have set to use a matrix came out extremely jumpy.

That bit rate is fine, but perhaps a little overkill for 720p in my opinion. A better question would be - do you have anything capable of playing it back other than a PC? Some Divx encoders won't let you encode to that high of a bit rate. You can encode H.264 with that bit rate. If you just want to play it on a PC, then no problem.

Do note that at the same bit rate, you should expect H.264 to outperform Divx. So that means that you could use a lower bit rate for H.264 encoding and get as good results as a higher bit rate with Divx. This is due to efficiencies in the H.264 codec that Divx lacks.

Finally, note that if you are doing resolution conversions in your encode (1080 down to 720, for example), unless you use the right filters to resize, you will get jumpiness. Also if your source is 1080i, going from interlaced video to progressive video (H.264 and Divx tend to be progressive) can provide its own set of challenges. You may need to get familiar with Avisynth to do resolution downsizing and/or interlaced to progressive encoding correctly.

[ckamc]

Overall I am just trying to create a constant quality but I am limited to a bitrate and thats what I was wondering. Basically I want to keep quality and filesize does not matter to me much except for how long I spend encoding.

For some reason mediainfo did not want to expand more than one branch with info about my mkv file. Using KMplayer it told me a bitrate but I was unsure if that would be considered the average since it told me the info right at the beginning.

Yes my video's are h264/x264 encoded, its when I went from 8GB to 3.6GB in one file that made me wonder if I am losing quality that when I put the video onto a proper 1080p display it would show.

I do not upscale or downscale any of my videos.

I stopped the video last night because 20hrs for a 720p seemed ridiculous, so I dropped the quality down to 5120, and if the quality looks good as my other 720p then I will make a custom profile of 6500 for 720p videos.

overall I am wondering if there is a way to calculate for constant quality when you don't have a desired file size.

p.s. my pc can play the files back no problem, but I want to encode them to my ps3 since its much more portable and a bluray burner is not in my budget at the moment.

[ckamc]

Well tried to send the file and it gave me a download error (file size of 5.9gb)

I thought the 4GB barrier with ps3 was a myth but looks like its true, can anyone provide me a bitrate calculator for bluray videos? I need to shrink this down to 3.9gb

[poisondeathray]

Jagabo already gave it: file size = bitrate * running time

Don't forget to account for both audio & video

[jagabo]

Any bitrate calculator that lets you specify the final file size will work.

The equation:

file size = bitrate * running time

is universal to all codecs.

It's just like:

distance traveled = speed * time

It doesn't matter if it's a plane, a car, or someone walking.