Video codecs in relation to file size

[Encodito]

Hey I have a question in relation to video editing, I dont know a whole lot about the terminology or HOW to do this type of stuff well... so if it sounds like idk what im talking about I would appreciate being corrected;

I'm interested in taking video files (200mb-2gb), cutting them up into 30-50 second portions and converting them to WebM's. I found a great (meh) program called Xmedia Recode which allows me to do it all-in-one quite effortlessly. The main issue I have is that final clips have to be smaller than 5mb, and as you can imagine taking a 30 second clip of (usually) 1080p video and keeping it below 5mb is very difficult. The program allows you to control MANY things; bitrate, resolution resizing, clip length etc etc etc (basically anything you could need to change, but i don't know what 90% of the features do AT ALL, so I leave them at the defaults).

My main issue is.. Normally I convert them using the VP8 codec which is fast, and keeps thing small, but unfortunately it forces me to make most files with 800-1250 bitrate dependent on clip length to keep under 5mb. I'm interested in keeping bitrate at 1500-2000; so is there any features or things that I'm not adjusting that can help me keep file size low with long clips in semi high bitrates? I typically downsize the resolutions to 854x480 (widescreen 480p) which seems to help.

The program does allow me the ability to utilize the VP9 codec, but from my experience it takes normally around 20-50x LONGER to encode the clips.. so basically a VP8 normally encodes in 30 seconds., but the 'same' file settings in VP9 will take anywhere from 15-30 minutes. The reason im interested in VP9 is from what i've read, and my experience using it, it allows for me to use even up to ~2000 bitrate for ~40 seconds of video and to keep files near 5mb... the only real drawback is the speed at which it takes to do so. Ive done some reading on other codecs such as H264 and H265 which seems to be in similar relation to VP8 and VP9... th newer of each pair offering better efficiency with smaller file sizes (from my understanding).. EIDT: To correct myself a bit, upon further inspection encoding with VP9 allows me to utilize similar bitrates to VP8 (~1000) but yields a crisper looking output

Should I be encoding to a different more efficient codec? Is there a better program out there to use? Am I missing some crucial features before encoding with my current codec (vp8?).

I do this 'work' with a desktop running an i5 4690k, so I dont really expect that encoding slowly to VP9 is the fault of my hardware(also read vp9 is just slower to encode in general)... though a Xeon or i7 would complete the tasks in a more timely manner, obviously.

Thanks in advance.

[Cornucopia]

FILESIZE = BITRATE * RUNNING TIME.

That's it. There is nothing else you use to calculate filesize. Running time is fixed for a certain program (unless you intend to do sneaky time-compressed material), so the only variable you have at your disposal to affect filesize is bitrate.

Now, things like resolution, codec, & settings will determine whether a given bitrate is efficient enough at providing the level of quality you need.
More efficient codecs (h265, h264, vp9) do this better than less efficient codecs (vp8, mpg4-asp, mpeg2...) - at the cost of complexity & speed of encoding - and some of those settings include speed - at the cost of other kinds of quality. But you can only squeeze so much quality out of a certain bitrate: it is an asymptotic function.

I would suggest that you revisit your endgame requirements and/or playback assumptions. 5MB per clip (even a 30 sec clip) seems a quite restrictive. However, if that is a rigid requirement that is out of your hands, it ought to be possible to come up with an h264 version at ~1.5Mbps of 720p30, using serious noise reduction, that would fit that criteria and give you a reasonable output. Bumping up to 1080p just for higher resolution's sake (while keeping the bitrate around the same) just creates more artifacts. If all your systems are cutting edge, you might could get by using h265 instead, otherwise, I don't recommend it. Personally, I do NOT recommend VP8 or VP9 except when a client is specifically asking for it for compatibility reasons. IMO, it's really not better than h264 (sometimes worse), and often has a speed penalty.

Scott

[Encodito]

Thanks for the info Cornucopia... See; even something as simple as filesize for videos was unknown to me.

I'm going to explore using FFMPEG + a GUI wrapper accessory and see if that facilitates the level of detail that im after in H264, as Xmedia Recode does not allow for H264 encoding.


Thanks!

[KarMa]

WebMConverter is a great little GUI for ffmpeg for making VP8/VP9 WebMs, and accepts avisynth.

I'm going to take a wild guess that you want to post these WebMs to image boards like 4chan/8chan/lolcow. In which case they may only accept VP8 and they may only accept video only .webm with no audio.

[Encodito]

WebMConverter is a great little GUI for ffmpeg for making VP8/VP9 WebMs, and accepts avisynth.

I'm going to take a wild guess that you want to post these WebMs to image boards like 4chan/8chan/lolcow. In which case they may only accept VP8 and they may only accept video only .webm with no audio.

look at this guy... figured me out

Yeah. I just grabbed that GUI and got it working.. tested it and it seems really nice besides the inability to queue.. but to have something that I can ensure stays below me intended file size limit and auto adjusts bitrate in a not-so-bad manner.. its really handy. Thanks.

& yeah you are right about VP8 and no audio.
Thanks guys