I have studied this problem and its solution in great detail and written about it in several places including the following blog posts.
The bottom lines are
a. Work from a project preset with 5.1 channel in its description
b. And, if your appropriate project preset is not offered with the 5.1 channel in its description, then you create one
that does include 5.1 channel.
This situation is not unique to Premiere Elements 12. It is seen in versions of Premiere Elements earlier than 12.
Please do not hesitate to ask if you need clarification on anything that I have written.
First of all thanks for your help !
I changed the preset files as indicated in your blog. Unfortunately it did not work. When I copy and adapt the presets the new preset files do not appear in the list of available presets within Premiere 12.
I create a PAL/AVCHD preset "AVCHD LITE 720p50 5-1 channel.sqpreset" and renamed the original one.
Within Premiere I can find the old preset with the extension original e.g. "AVCHD LITE 720p50 - original" but not the ones I have created.
Never tried this with Premiere Elements 12 and the AVCHD LITE 720p50.
I will give that a try and report back.
Thanks for reporting on your results.
Did you try the methods as written for 1080p?
You need to give this another look. You can create a PAL AVCHD LITE 720p50 5.1 Channel for the new project dialog choices in Premiere Elements 12 using the principles that I used in my blog for doing this for 1080p. I just did it.
This should be a quick and easy procedure. Let us see what happened in your case.
In your case, the first instruction would be to copy the file name AVCHD LITE 720p50.sqpreset file found in Premiere Elements 12 Windows 7 or 8 64 bit path of:
Local Disc C
Adobe Premiere Elements 12
and in the AVCHD Folder is the AVCHD LITE 720p50.sqpreset file that you copy (paste to desktop for now).
Follow the rest of the instruction in the blog post.
These following specific Notepad changes are the same whether the Notepad document reflects Premiere Elements 11 1080p or your Premiere Elements 12 720p.
And where it says
When the changes are made, are you placing a new file specifically named
AVCHD LITE 720p50 5.1 Channel.sqpreset in the correct Program Files location as per the path described....?
And, you can get a AVCHD.mp4 (720p50) 5.1 channel file from Publish+Share/Computer/AVCHD with the preset of MP4 HD720p50 with adjusts under the Advanced Button/Audio Tab. I just did.
I will write up the above for inclusion in my blog for 720p and obtaining a 720p 5.1 channel version of the preset.
Please review and let us know the outcome.
I have just written up the 720p50 5.1 channel and 720p60 5.1 channel project presets details into a blog post.
Please check it out and see if we can figure out the differences between us.