rendering at cam bitrates / media player choice

Mindmatter wrote on 5/20/2015, 4:26 AM

Hi all,

I've been wondering about max bitrates for mp4 renders, as some media players sometimes seem to have issues with higher bitrates and create artifacts or severe audio sync problems.
So my current, not yet edited project is made on the sony PMW 320, which records mp4 at 37,9 Mbps. In order to get the best possible render quality ( will be shown on a seminar on projectors , and later on a website ), should I keep that bitrate for the final mp4 if possible? Or should I choose a different codec altogether?
Also, what's your preferred media player you check your final, finished product with?
Thanks!

Comments

musicvid10 wrote on 5/20/2015, 7:29 AM

mp4 in Handbrake is my choice.

Your camera AVCHD stores data much less efficiently than a delivery encoder such as x264, so a comparison of bitrates is meaningless.
That's also why camera footage doesn't play back as well on consumer systems.

It's 1) playability, 2) quality, and 3) compression, in that order.
If the mp4 stutters on playback, back off the peak bitrate. (The handbrake command is vbv-maxrate.

riredale wrote on 5/20/2015, 10:19 AM

Why not try an experiment where a very short section is rendered to mp4 at several different bitrates? I suspect you can get away with a bitrate FAR LOWER than 30Mb/sec on HD material.

Mindmatter wrote on 5/20/2015, 11:12 AM

Thanks to both of you.
Disk space and file size being no issue, I'd basically just like to know the best possible, cleanest, shiniest and nicest output format and bitrate possible.
Not entirely clever on the technical intricacies of codecs, I was wondering: Is mp4 really an AVCHD codec? Didn't think so.

musicvid10 wrote on 5/20/2015, 11:45 AM

Both are AVC codecs. Their format specs AND uses are quite different.
The best copy is a copy. But AVCHD Transport Streams are not designed for delivery, and they take up a LOT of space..

So one finds oneself compelled to make some compression "choices."
You simply can not have it both ways, sorry.

The optimal delivery compression is determined by SOURCE COMPLEXITY, not some arbitrary bitrate target. Simply put, no such thing exists, because no two sources are the same!

A slideshow video works perfectly well at 200 Kbps; that's more than 100 times smaller than a high detail, high motion video scene would need to be able to sustain for the same delivery quality.
Knowing this basic fact will be very important for you going forward, assuming that producing a playable outcome comes first:"

pilsburypie wrote on 5/20/2015, 3:49 PM

I have been experimenting with the handbrake method mentioned on here. I have come to the following conclusion:

Before I used the Handbrake method, I just rendered my AVCHD footage on the Sony AVC template 1080 50p 25, 999, 999 bps. (or whatever the max in 11 pro allowed). I got great looking footage. Pleased as punch with it when played on my TV via PS3.

If I wanted to upload to youtube, the file size was a problem - not because youtube didn't allow, just because upload was so long. Youtube recommends 10mbs mp4, but even so, file sizes were big. Plus I'd say 10mbs was the turning point of my footage - basically where I could clearly see degradation. Going below 10mbs was bad. Blocky as hell on a smooth colours.

Then I tried Handbrake. I can now get real good looking footage for youtube at 8mbs - much better than the 10mbs straight from Vegas. But, when I rendered at higher bitrates on the Handbrake method I couldn't really tell a difference. I simply assume that when you hit a certain quality point determined by your cameras capability, your eyes find it hard to distinguish no matter how high a bitrate you render to.

In the same vein, I still use Handbrake for my big files to be played over the PS3, simply because it is faster and I guess if it is doing such a good job at low bitrates, it must be performing equally as admirably at the higher bitrates even if I can't tell!

From Musicvid10's statement: Size, Quality, Speed - pick 2, I'd say I'll have all 3 using Handbrake.

farss wrote on 5/20/2015, 5:43 PM

[I]"I was wondering: Is mp4 really an AVCHD codec? Didn't think so."[/I]

MP4 is a wrapper not a codec. Your PMW 320 records MPEG-2 in a MP4 wrapper.

Bob.

Mindmatter wrote on 5/21/2015, 5:25 AM

Most excellent info, thanks to all of you for chiming in!