How to tell Mbps on AVCHD?

I

ian_h

Active member
How do you get info on what Mbps rate the AVCHD is recording at? I'm running the 40Mbps AVCHD High Reliability patch and when Logged and Transferred into FCP in Prores LT it's being reported as 9.4-9.7 Mbps.

Daylight, detailed flower bush shot.

Prores HQ on the same clip in FCP is reported at 21.7 Mps. These are some way off the 40Mbps setting, or is it the Prores conversion that's doing it?

How do I find out the original AVCHD bit rate?

thanks, Ian
 
i think prores is converting it at that rate. Someone a while back was wondering why his clips were reporting 17MB, it was the export settings on prores

to really see bitrate view the native mts file on a viewer that shows bitrate info. splashlite works well but it does not work on mac. remember codec is variable so you will not always see 40Mbit results.
 
Quick way I test is to shoot some high action cartoons etc with lens zoomed in to full lcd screen..
Shoot approx 20 sec bursts...
Check the files by size and divide by clip time in seconds..
this give MBS, then multiply by 8 this gives average mbps....

I run full C hack, very stable with class 10 cards , Sandisk extreme are superior in all my testing..
I hit 50.144 mbps in highest points...

cheers...
 
Thanks. Hmmm... interesting. The daylight AVCHD files are running about 37 Mbps according to MediaInfo - and the Prores LT encode around 80. The HQ encode around 180. Quite a different story to FCP telling me the LT files are under 10 Mbps....
 
Those Pro Res clips are mega-BYTES per second. They are much larger than the original AVCHD files.
AVCHD is measured in terms of mega-BITS per second. Be careful not to confuse megabits with megabytes.
Remember: 8 bits = 1 byte
megabytes are abbreviated "MB" (capitalized) while
megabits are the lower case "mb"
 
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Toast Player on the Mac is not only an excellent AVCHD player, but also shows the running data rate.
 
I've been looking at the bitrate of my footage, though I find I get a couple different results. Windows 7 seems to give average bitrate info for video files, and is often showing my footage, high detail shots, at about 20-40 (though very rarely at 40) mbs. I tried bitrate viewer to see what it would say, and it shows my files at being 15-25 mbs.

Any ideas about the discrepancy?

I'm running C settings btw.
 
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