Here's how Articulate Storyline encodes videos in your courses, based on their original file format and the output options you choose when publishing:
|Original Video Format||Flash Output||Mobile Output||HTML5 Output|
|MP4||Re-encoded to MP4||Re-encoded to MP4||Re-encoded to MP4|
|FLV (no alpha channel)||Encoded to MP4||Encoded to MP4||Encoded to MP4|
|FLV (with alpha channel)||No change (FLV)||No change (FLV)||Encoded to MP4*|
|SWF||No change (SWF)||Not supported||Not supported|
|All other file types||Encoded to MP4||Encoded to MP4||Encoded to MP4|
*Alpha channel transparency isn't supported in HTML5 output. As a result, FLV videos with alpha channels will be encoded as MP4 videos in HTML5 output.