AF100 - LPCM audio mode and post/computer compatibility

I've usually continued using Cineform's NeoScene with a Canon 5D2 files and Premiere Pro CS5 because I like having the 10bit resolution. However if I process my AF101 PAL files in NeoScene the LPCM audio is currently mangled and unusable.
It's easy enough to bin the NeoScene audio and go back to the source though and PP CS5 is ok with the LPCM.
I imagine Cineform will get to using LPCM at some stage though as it's going to be much more common as the amount of AF100 material increases.

David T
 
Oliver Rush said:
How bad is the quality loss with AC3 over LPCM? Am I loseing much really?
Click to expand...
Well, that's an interesting question -- I don't think anyone has done a side-by-side test. All prior AVCCAM cameras have offered only AC3, and I can't think of any complaints about quality that have been raised here on the forum, and the HMC150 has been out for about two and a half years, so you'd think that if it was bad we would have heard. I would think that for dialogue it would be difficult to impossible to tell the difference; dialogue isn't that hard to compress and I'm sure AC3 does a great job (that is assuming on my part, but I think it's a safe assumption). Recording a symphony, well, that might be a bit more challenging and if you're going to tell the difference between them, that'd probably be the place. But how do you test for that? You can't just point a mike at a stereo and play a CD, because then you're introducing all sorts of other issues into the mix (including the quality of your speakers, the quality of the CD player, the quality of the original CD itself, etc). I guess the only way to really know would be to set up a live recording of a symphony (I'm using a symphony as an example because of the extreme variations in dynamic range that a symphonic performance frequently exhibits).
 
That is interesting that you posted this, Barry. I recently did a shoot and I had switched the audio to LCPM. I have Final Cut version 6.06, and I had a devil of a time importing the footage.
I had some fourteen-minute clips that simply would not import. I finally cut them up into one and two minute pieces, and I was able to import them.
I do have audio on them, but I had been wondering if the problem was caused by switching the audio.
 
It was certainly caused by switching the audio, and the latest version of FCP fixes that bug so you can import footage of any length properly.
 
Seamus McFlannel said:
That is interesting that you posted this, Barry. I recently did a shoot and I had switched the audio to LCPM. I have Final Cut version 6.06, and I had a devil of a time importing the footage.
I had some fourteen-minute clips that simply would not import. I finally cut them up into one and two minute pieces, and I was able to import them.
I do have audio on them, but I had been wondering if the problem was caused by switching the audio.
Click to expand...

I still use Final Cut 6.06 and all the footage I've ever shot with my AF100 imported just fine, and I've never used AC3, only LCPM. I've also transcoded clips exceeding 20 min. I wonder if it's a hardware thing. I'm using a 2008 15inch MacBook Pro with a 2.6 ghz core 2 duo and 4 gigs of ram for transcoding.
 
Well, I don't know why you've been lucky with it, but I thought that Apple announced that part of their latest update was to add or fix compatibility for LPCM mode in AVCCAM...
 
It worked for me in FCP 6.06, but I woudn't trust it if I were handing footage off to a client. Why risk it? This is one of those little gotchas that can really wreck a good shoot.
 
DrHST said:
It worked for me in FCP 6.06, but I woudn't trust it if I were handing footage off to a client. Why risk it? This is one of those little gotchas that can really wreck a good shoot.
Click to expand...

I hear what you are saying, but I didn't know until right now that FCP 6 has issues and I must have given 30 - 40 hours of transcoded footage to clients since I've got my AF100 with no problems, so I know on my system with my set up it works perfectly. It is probably a compatibility issue with specific hardware. I am curious why others are having problems.
 
Barry_Green said:
Version 7.0.3 was released to address LPCM issues. Sometimes it would work fine, sometimes it would just take forever to import LPCM clips. This has affected Sony NXCAM and Panasonic AF100 LPCM footage.

http://discussions.apple.com/thread.jspa?messageID=12287296
Click to expand...

Interesting. It takes 1 - 1.5 real time to transcode clips. I addressed the speed issue in another thread back in January sometime and everyone said that is normal. What kinds of transcoding speeds are people getting in FCP7?
 
In FCP, it's pretty slow .. 1 to 1.5 seems about right. You can turn off import of the video and it
seems just as slow. On the P2, it was quick .. I miss P2 ... can we have it back please? :-)

jeff
 
jmarkham said:
In FCP, it's pretty slow .. 1 to 1.5 seems about right. You can turn off import of the video and it
seems just as slow. On the P2, it was quick .. I miss P2 ... can we have it back please? :-)

jeff
Click to expand...

So you are talking about FCP7 then? If so my experience with FCP6 is identical to FCP7.
 
jmarkham said:
In FCP, it's pretty slow .. 1 to 1.5 seems about right. You can turn off import of the video and it
seems just as slow. On the P2, it was quick .. I miss P2 ... can we have it back please? :-)

jeff
Click to expand...

Running 7.0.3 here and I'm getting somewhere in the ballpark of 5-6x realtime if not faster (transcoding to ProRes HQ or LT). The AVCCAM importer can use all the cpus in the Mac Pros so it goes very quickly - as quickly as P2 did, if not faster. This is just my experience and it remains phenomenological only. I'd be happy to actually run some tests at some point when work calms down.
 
You must log in or register to reply here.
Back
Top