Good 720p AVCHD bitrate for home movies?

[amirh1]

Hi,
I've seen various posts on recommended bitrates, but they had to do mostly with movies that may require higher rates due to moving scenes.

I shoot a lot of home videos of my kids with my camera at 720p. I want to get a decent bitrate to be able to watch on my 55" LCD without too many artifacts, however it doesn't have to be "perfect" and also there aren't a lot of moving scenes. I want to be able to store them without buying a HDD every month.

Any suggestions on what would be a good bitrate? If you could also tell me what's the maximum that beyond it I'd probably wouldn't notice any difference that would be very helpful.

Thanks!!

[JEEB]

TL;DR Depends completely on your source(s). I'd guess in your case I'd rather just use the crf mode to find the highest crf number that gives you watchable quality.

That way you can use it on all of your videos and get very similar quality and -- the best part comes here -- you only use as much bitrate as you need (plus you don't need to do a second pass with crf, the process only needs one pass).

[Dark Eiri]

Try CRF 21 or 20. It's a good start. If the source is really compressible, even CRF 18 will give small filesizes.

[amirh1]

so i know crf isn't directly translatable to bitrate. I'm actually asking because of the settings on my camera: I can set a few bitrate levels, highest being 15Mbps. I was wondering if it's too high and I can maybe bring it down to 10 without noticeable loss.

I know there aren't hard and fast rules, but people out there are storing 720p home videos - I was wondering what bitrates they're typically using?

Thanks!

[Audionut]

Why don't you take it down to 10Mbps and see for yourself. Most of my crf18 720p encodes come out around 5Mbps, having said that, the cameras encoder is probably crap. My personal preference would be to set it at 15Mbps and use x264 to re-encode it smaller.

[Fr4nz]

My 2 cents.

Suggestions given to you from the above users are really valid.
My point of view is that a bitrate between [3.5-5] mbps is quite good for 720p, especially if you filter some noise from the original source with a good filter (for example fft3dGPU). x264 really makes an amazing job...

[JEEB]

so i know crf isn't directly translatable to bitrate. I'm actually asking because of the settings on my camera: I can set a few bitrate levels, highest being 15Mbps. I was wondering if it's too high and I can maybe bring it down to 10 without noticeable loss.

If you're thinking about the bitrate you'll set for your source, select it as high as possible. Cameras' encoders are usually bad in compression (made for being quick and to use not so much power), and the worse source you have to handle, the more headache.

Of course, it's all up to you, if you can't see the difference and don't want to use extra hard drive etc. space for the sources, sure.

[pkirill]

video bitrate hardly depens on its content
the best solution is to select comfortable CRF value, my choise is 19
also it is reasonable to play with noise redusers, that will allow to reduce the resulting bitrate significantly

[7ekno]

I use MCTemporalDenoise(settings="low") + appropriate levels() at --crf 18 with my 720p 18Mbps MTS's from a Panasonic camera ;)

Resulting encodes are usually 50%-75% smaller with no decernable quality loss ;)

7ek

[Dark Eiri]

Oh yeah, for the camera encoder you should set the highest possible bitrate. Those are in no way comparable to x264 in quality.

[Audionut]

video bitrate hardly depends on its content


Bitrate is directly related to content.

A static scene requires less bits to maintain the same quality as a scene with high motion.