AF100 - LPCM audio mode and post/computer compatibility

B

Barry_Green

Moderator
The AF100 extends Panasonic's AVCCAM AVCHD format by adding a new uncompressed LPCM (linear pulse code modulated) audio recording format, in addition to the existing AC-3 compressed audio.

Since this is a new recording format, there may be some NLE or computer playback compatibility issues.

I'm starting this thread so we can find out what works with it, and what doesn't work, as soon as possible, and if we find anything that doesn't work, hopefully we can use that info to ask the software manufacturers for updates.

Here's a simple file recorded on an AF100 in LPCM mode, some bars & tone, that you can download and try on various software programs:
http://www.mediafire.com/?9jcrzc6etje43i3

Tested:
Adobe Premiere Pro CS5 v5.0.3: works
Sony Vegas 9.0B, 10a, and 10b: works
Apple iMovie '09: works
Apple Final Cut Pro Log & Transfer in version 7.0.3: works. Note earlier versions may or may not appear to work, but 7.0.3 was released specifically to fix LPCM issues in prior versions
EDIUS 5.51: works
Nero ShowTime 9: works
VLC 1.1.5: works
AVS Video Converter 6: works
Prism using FFMpeg library: works
ClipWrap 2.0: works
Western Digital LIVE Player: works
Avid MC 5.0.3.5: works

NewTek SpeedEdit 1.5: no audio
Windows Media Player 12.0.7600: no audio
MPeg Streamclip: didn't work


EDIUS Neo 2: untested
 
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Great idea, Barry! And to other users, don't forget to put specific versions of each app.

Tested:
VLC 1.1.5: works
 
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Avid MC 5.0.3
via AMA: not supported
via Import: crashes the software (on mac) the error message is related to audio ("Imports/AvchdAudioImpConsumer.cpp")

I do not have the latest patch.
 
Barry_Green said:
The AF100 extends Panasonic's AVCCAM AVCHD format by adding a new uncompressed LPCM (linear pulse code modulated) audio recording format, in addition to the existing AC-3 compressed audio.
Click to expand...

The good news is that you can select the AC-3 audio when recording to the PH mode if your current NLE does not support the LPCM audio. This is covered in the Recording Setup portion of the manual, Volume 2, on page 56.
 
Barry,

What's the noise floor like for AF-100 ?

i.e. Feed the camera a 1 kHz tone ( either MIC or LINE level ) and adjust the level on the camera to read the tone as -12 dB, then kill the tone and see what the noise-floor is for the camera that is still recording

I know that this is more of a theoretical test, as it doesn't take into account self-noise from the MIC or the environment you might be recording in, but it does provide some idea of how the camera performs under ideal conditions.

This is one area where I am not too happy with my HMC-150, as it shows a noise-floor of about -63 dB, which is fine for optimal recordings, but doesn't leave a lot of room when things go wrong. On the other hand the Panasonic HS700 consumer camera shows a noise-floor of about -82 dB feeding a 1 kHz tone from a Sound Devices MixPre run through a BeachTek DXA-2 passive XLR adapter, which really surprised me the first time I did the test.
 
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TheDingo said:
Barry,

What's the noise floor like for AF-100 ?

i.e. Feed the camera a 1 kHz tone ( either MIC or LINE level ) and adjust the level on the camera to read the tones as -12 dB, then kill the tone and see what the noise-floor is for the camera that is still recording

I know that this is more of a theoretical test, as it doesn't take into account self-noise from the MIC or the environment you might be recording in, but it does provide some idea of how the camera performs under ideal conditions.

This is one area where I am not too happy with my HMC-150, as it shows a noise-floor of about -63 dB, which is fine for optimal recordings, but doesn't leave a lot of room when things go wrong. On the other hand the Panasonic HS700 consumer camera shows a noise-floor of about -82 dB feeding a 1 kHz tone from a Sound Devices MixPre run through a BeachTek DXA-2 passive XLR adapter, which really surprised me the first time I did the test.
Click to expand...

I'd be interested in this as well, but it should probably be a separate thread.
 
From Barry and Adumas's posts it looks like AVID does not currently work with LPCM... can anyone confirm this ? So... is the advice to cameramen who don't know what system will be used to edit their AF100 material "only use AC3, do not use LPCM" ?

I've searched Google for "Avid LPCM" and there is nothing useful out there... apart from this thread!
 
Barry I'd like to note that it works in both Final Cut Pro 6 and Final Cut Pro 7. Your original post just said Final Cut Pro and could maybe lead to confusion for some.
 
John Hoare said:
So... is the advice to cameramen who don't know what system will be used to edit their AF100 material "only use AC3, do not use LPCM" ?
Click to expand...
If you know you're going to be cutting on Avid, give the editor an LPCM clip to try -- if it works, great. If not, definitely use the AC3 mode instead of LPCM.
 
Updated again. Apparently FCP issued an update in September, version 7.0.3, which fixes any outstanding issues with LPCM audio. Prior versions of FCP may be able to import clips, but sometimes the import would happen extremely slowly, or could even crash. 7.0.3 is updated to properly work with LPCM audio.

Also, Avid has released a patch that addresses the LPCM support; version 5.0.3.5 of Media Composer adds support for LPCM mode and also for spanned clips.
 
what i'm interested to know is the difference in bitrates between the ac3 and lcpm, i would assume the lpcm to be significantly higher, and if so, does that increase the overall VBR or does the video bitrate take a hit
 
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