PCM audio track not playing on computer

[Andrew Taylor]

I would like to continue here a tread I started on the Canon XA/Vixia forum (http://www.dvinfo.net/forum/canon-xa-vixia-series-avchd-camcorders/531324-audio-camera-not-pc.html). I have a few video files that were recorded with a Canon XA20 in 28mbps LPCM (59.94P) so that the audio is in PCM format. The audio plays fine on the camera, but there is no audio once I transfer the files to the computer (Windows 7). The audio does not play using the latest version of VLC or Media Player. When the files are imported into Premiere Pro 5.5, there is no audio track. This happens with the .MTS files on the SD card, the same files that were copied and pasted onto the computer's HD, and the files that were transfered to the computer using the Data Import Tool that came with the camera.

I used Audacity to rip the audio from the .mts files (on the SD card and on the computer), and all I got was static.

What I'm looking for is a way to transfer the .mts files to the computer retaining the audio track, or a way to rip the PCM audio from the .mts files to import that audio into PP.

Any suggestions will be appreciated.

[Gary Nattrass]

Have you checked the sample rate as some PCM files can be 32k or less.

Most software only reads 44.1 or 48k.

[Andrew Taylor]

Media info indicates the sample rate is 48KHz (see below for full info)

- - - - - - - -

Audio
ID : 4352 (0x1100)
Menu ID : 1 (0x1)
Format : PCM
Format settings, Endianness : Big
Format settings, Sign : Signed
Muxing mode : Blu-ray
Codec ID : 128
Duration : 32s 12ms
Bit rate mode : Constant
Bit rate : 1 536 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Delay relative to video : -33ms
Stream size : 5.86 MiB (0%)

- - - - - - - -

[Battle Vaughan]

Not getting audio from an .mts file is a well-known problem, there are a number of references to it on the web. The Adobe forum says support for avchd with pcm audio was not added to Premiere until CS6, so you are probably lacking the support you need in 5.5.

One solution (which I have not tried) was demonstrated on youtube, simply renaming the file to .avi did the trick in the example. Not sure this always works, but worth a try.

Or converting the file in a file conversion program to another format should do the trick. There is likely a codec problem involved. The Blu-ray muxing looks like a clue, as well.

[Seth Bloombaum]

Have you installed any codec packs, which promise to play back everything? Usually a bad idea...

In addition to their frequent function as spyware bait, they can play havoc with various playback and encodes by rewriting system pointers from system or known-codecs to semi-functional or bad codecs.

Battle's thought on Premiere 5.5 vs. CS6 or CC seems well founded, but doesn't explain lack of success on VLC, which ought to play about everything, if its codecs haven't been messed with...

PS. I have some XA20 files on my system - MediaInfo shows identical info in the audio section as what you posted above, including the muxing mode.

PPS. I've never used the data import utility. I just drag the card contents into my computer, using OS-level copying. You should try that!

PPPS. Have you had success with this system and XA20 files in the past?

[Andrew Taylor]

I tried all the recommendations I found on different forums, including changing the file extension to .mp4 and .avi. I also changed the extension from upper case to lower case (someone mentioned that worked for them). I also followed the suggestion of using VLC media to convert the .mts file to .mp4, but the output generates an "unknown video format" in Media Player and PP 5.5

It seems to be the case that there is no single solution, and different people report different results (good or bad) with the same approach.

The only thing I have not done is transcode the files as I could not find specific, straightforward instructions.

[Andrew Taylor]

Originally Posted by Seth Bloombaum

Have you installed any codec packs, which promise to play back everything? Usually a bad idea...

I didn't install any codecs. I would only trust Microsoft as a source, or a well known company (e.g., Adobe, Canon, etc.)

Originally Posted by Seth Bloombaum

[b]Battle's thought on Premiere 5.5 vs. CS6 or CC seems well founded, but doesn't explain lack of success on VLC, which ought to play about everything, if its codecs haven't been messed with...

Every other discussion I've read indicates that Media Player doesn't play PCM audio, but VLC does, indicating there is audio on that video file. But in my case, VLC does not play the audio either.

Originally Posted by Seth Bloombaum

[b]PPS. I've never used the data import utility. I just drag the card contents into my computer, using OS-level copying. You should try that!

I used copy/paste as my initial transfer method, because that's how I normally transfer AVCHD files from the SD card to the HD. When that did not work, I installed the Data Transfer Utility, which was kind of useless (you cannot pick and choose what to transfer, you can only choose to transfer all files on the SD card, or the ones that have not been transferred yet). All the Data Transfer Utility did was to rename the files from 0000001.MTS to 20160302.mts, thus adding the date to the name and changing the extension to lower case.

Originally Posted by Seth Bloombaum

[b]PPPS. Have you had success with this system and XA20 files in the past?

I only got this system recently. I tested different recording modes. The files recorded in 28Mbps (non LPCM) play fine on the computer, audio included. Media Info shows those files use an AC-3 codec. The files recorded in 28 Mbps LPCM never played the audio on the computer.

[Andrew Taylor]

Originally Posted by Battle Vaughan

The Adobe forum says support for avchd with pcm audio was not added to Premiere until CS6, so you are probably lacking the support you need in 5.5.

If there was a way to extract the audio from the .MTS files, I could use that in the PP 5.5 timeline (as opposed to buying CS6). I tried converting the .MTS file with VLC media, and I also tried extracting the audio with Audacity. None of them worked. VLC created a file that was not readable, and Audacity created a file that was pure static (or white noise).

[Andrew Taylor]

Originally Posted by Seth Bloombaum

[b] PS. I have some XA20 files on my system - MediaInfo shows identical info in the audio section as what you posted above, including the muxing mode.

And how do those files behave? Do they play only in VLC? And, do you import them into Adobe CS6, or into something else?

[Battle Vaughan]

Could you maybe post a few seconds of a clip? Hard to diagnose flying blind. I have PCM sample files that work fine in vlc, Windows Media player and Adobe CS4, even. (Don't know why this works, see my above info about pcm support in Adobe. ) Maybe we can figure out the problem...

[Andrew Taylor]

Here's a few seconds of a representative video. The audio should be street noise (cars, horns, etc.):

https://drive.google.com/file/d/0B2s...ew?usp=sharing


And after I uploaded the video to Google Drive, I played the online video to make sure it was the right one, and to my surprise, the audio played. But still no audio in VLC or PP 5.5, so I still need to extract that audio somehow.

[Seth Bloombaum]

Originally Posted by Andrew Taylor

And how do those files behave? Do they play only in VLC? And, do you import them into Adobe CS6, or into something else?

They play in VLC, usually I'm editing in Premiere CC. This is on a Mac.

Originally Posted by Andrew Taylor

Here's a few seconds of a representative video. The audio should be street noise (cars, horns, etc.)...

Your audio doesn't play in my VLC. I do hear it in Premiere CC, and in the Google player on the web page (Firefox).

This is strange. If you have access to the XA20, can you try AVCHD/24Mbps LPCM/PF29.97? That will exactly match the settings we use at the college... It's 30p rather than the 60p you've been working on.

[Andrew Taylor]

Here's another clip I just took from the TV (nature show):

https://drive.google.com/file/d/0B2s...ew?usp=sharing

This was recorded in 24Mbps LPCM at PF29.97. I can hear the audio in VLC now. I also have an audio track with proper audio in the PP 5.5 timeline.

Interestingly, Chrome tries to use Flash player to play the Google Drive file (which I have disabled on that browser). The video recorded at 28Mbps defaulted to the HTML5 player.

[Battle Vaughan]

This must be a missing-codec issue. I took your .mts file into my file converter (Brorsoft Blu-Ray video converter) and easily and quickly converted the audio to .wav and .ac3, and the entire project into mpeg2 and .mp4 (h264) with no problem. There is a free trial of Brorsoft, although I suspect a there are a host of similar programs. My current version of vlc doesn't see the audio at all.

So possibly the simple solution is just to convert the clips to something else in a similar program. Usual disclaimer, no connection or interest in Brorsoft other than satisfied user.

http://www.brorsoft.com/video-converter/

[Andrew Taylor]

Thank you for that information. When both VLC and Audacity failed to convert the .MTS file or extract the audio, I just didn't want to start trying one piece of software after another until one of them worked.

I'll see if the Brorsoft trial has any limitations (length, watermark, etc.).

My choice for future video projects then will be between 24Mbps with LPCM or 28Mbps with Dolby (AC-3). I don't know enough about the tradeoffs between those choices, so I'll have to do more reading on that. Although I wonder if 28mbps with LPCM and 30fps would also work. I'll try that when I can.