Need more info. What video file are you using? Some HD Sony video flies have propitiatory coding that needs a licence to use/read.
Thanks for replying, My video has come from a Canon Eos 5 MkII SLR camera. I've opened the file in Photoshop and everything seems fine, made adjustments and edits, can hear sound on playback. Only when I export video I have no option to include sound even when choosing the Quicktime option.
Here is a past post, hope this helps.
I do not have my CS5 Extended handy, so will go from the Premiere Pro (Adobe's video editor) side of the street. Bear with me on this, as PS-Extended might do things a bit differently.
When one is Exporting an AV file, there are two things that must be set:
Exporting both Audio & Video (in PrPro, these are done via checkboxes in the Export>General dialog screen)
Then, one must set Multiplexing * on the Export>Multiplexing dialog screen, to anything but "None." The choice is usually "DVD."
It's the Multiplexing Tab, that many miss. If set to None, then there will be two separate Export files - one for the Video stream, and one for the Audio stream.
Hope that gets you close, and sorry that I cannot open things up, and give you the exact screens and tabs in PS-Extended.
* Multiplexing is the combining of both the Audio & Video streams into a single, discrete file. Multiplexing is usually OFF by default, though in PrPro, it's a "sticky," in that it retains the last setting, so if the user wishes to make a change, they must do so manually, and that setting will then stick, until changed again. The Export of separate files for Audio & Video is most often used, when one is doing the Export to go to a DVD, or BD authoring program, like Adobe Encore. It works best with elemental streams, rather than muxed files, and especially with MPEG Audio.