How can I compress my .avi into .mp4 zlib?

[synnchan]

I use MKVToolNix GUI to compress my .avi files into .mkv with the zlib compression algorithm. But I'd like to know if there's a way to do the same process, except turning the file into .mp4 instead of .mkv.

Can someone help me?

[netmask56]

Do what you are doing and then use MkvToMp4

[jagabo]

zlib is not a "standard" codec for the MP4 container so you may have limited playback/editing compatibility.

[johns0]

What you are doing is just remuxing,not compressing,any special reason you need avi (xvid?)to be mp4?

[raffriff42]

Had never heard of zlib (a ZIP-like lossless compression scheme) being used for video. I thought it was mainly for on-the-fly compression of HTML. It seems zlib is used only on the headers, not the audio or video data, which of course is 99% of the total. The effect on total file size must be minuscule.
So don't worry about it
https://en.wikipedia.org/wiki/Zlib#Applications
https://www.matroska.org/news/compressed-headers.html
https://forum.videohelp.com/threads/341226-Header-stripping?p=2219825&viewfull=1#post2219825

[jagabo]

There are also zlib based lossless codecs.
https://www.fourcc.org/zlib/

Keep in mind that entropy encoding, similar to zlib's DEFLATE algorithm (a variation on Lempel–Ziv), is the last step of most video compression codecs. So compressed video isn't further compressed by such techniques.

[synnchan]

Do what you are doing and then use MkvToMp4

Not working, it gives me an error. I get a red (X) on Video after starting the process.

What you are doing is just remuxing,not compressing,any special reason you need avi (xvid?)to be mp4?

I do what I do when I upload my stuff to YouTube since it accepts .mkv. Twitch on other hand only accepts .mp4 (it introduced a video upload feature recently).

[jagabo]

I don't think the MP4 container officially supports any lossless video codecs.

http://www.mp4ra.org/codecs.html

You should try using x264 in lossless mode. I don't know if Twitch will accept lossless h.264 in MP4.

But why would you want to encode with a lossless codec for upload to video sharing sites?

[synnchan]

I don't think the MP4 container officially supports any lossless video codecs.

But why would you want to encode with a lossless codec for upload to video sharing sites?

Why not?

[LigH.de]

YouTube will certainly recompress the uploaded video again, for each offered same or smaller resolution. Therefore it may be useful to upload good quality because it will get worse ... but uploading losslessly compressed video is mostly a waste of internet bandwidth. Video with hardly recognizable loss will be suitable (e.g. x264 with CRF 15..18 is usually fine).

If you have artifical content (e.g. game screen recordings with sharp edges, saturated colors, and fine structures), upscaling your video might be useful, to preserve some sharpness while YouTube will reduce the resolutions. But really lossless encoding won't preserve more quality than "visually transparent" lossy encoding, just blow up the file size more than necessary.

[synnchan]

Oh. Yes, I noticed that while my videos look perfect if watched from my computer, their quality decrease a lot once on YouTube, but I was still in a bit of doubt.

Thank you for the confirmation.

[netmask56]

In MKV files that have it it generally only relates to a subtitle track - miniscule and indeed many media players have problems with compressed headers. For awhile the default setting for MKVMergeGui was ON but now it is OFF. I wouldn't use it as it offers no real size advantage. Maybe 1% of 16 to 32K typical srt file size

[jagabo]

ffmpeg includes a zlib video encoder and decoder. I was able to produce AVI and MKV files with zlib compressed video with ffmpeg:

ffmpeg -i %1 -vcodec zlib "%~dpn1.zlib.avi"
ffmpeg -i %1 -vcodec zlib "%~dpn1.zlib.mkv"

But, as I suspected, it refuses to make an MP4 video with zlib:

ffmpeg -i %1 -vcodec zlib "%~dpn1.zlib.mp4"