Combining video-only mp4s and mp3 audio, then publishing to HTML5
We have a client that gives us instructional videos in MP4 format. However, the audio in his files are very quiet. I would like to figure out a solution to making his audio louder without resorting to a professional video editor.
On way I could do this is to split the MP4 file in a video-only MP4 file, and exporting the MP3 audio from the original MP4. (VLC media player can do this.) I can then use Audacity to boost the audio, and edit it if need be. I can then add them both back to a Storyline slide timeline.
I have done this, and not noticed any if all sync issues. The program material is not terribly sync-needy. However, this only seems to work with a Flash-based publishing build. The audio doesn't play in the HTML5 build.
I know that Storyline, when it publishes, obfuscates file names for things like MP4, MP3, SWF, JPGs etc. I thought that perhaps the HTML5 side wants to see .OGG files; so I exported versions of the MP3 audio files, found the obfuscated audio file MP3 names, and copied these names to the OGG files, then placed them in the story_content sub-folder of my build alongside the original MP3 audio files. This did not work.
So I guess I have a couple of questions:
1) Can HTML5 handle simultaneous MP4 and MP3 playback as separate files, or do they have to be all one file?
2) If HTML5 can handle it, is this a limitation of Storyline?
3) If this is not a limitation of Storyline, was I on the right track with the extra audio file inclusion idea listed above?
Thanks for any illumination on this matter. If we have to get a video editor to just boost the audio portions of the videos, we will do it but I'd rather not.