
PASS SourceBuffer added to activeSourceBuffers list when its only audio track gets loaded (and thus becomes enabled). 
PASS SourceBuffer added to activeSourceBuffers list when its only video track gets loaded (and thus becomes selected). 
PASS Active SourceBuffers must appear in the same order as they appear in the sourceBuffers attribute: audio is first sourceBuffer, audio media appended first 
PASS Active SourceBuffers must appear in the same order as they appear in the sourceBuffers attribute: audio is first sourceBuffer, video media appended first 
PASS Active SourceBuffers must appear in the same order as they appear in the sourceBuffers attribute: video is first sourceBuffer, audio media appended first 
PASS Active SourceBuffers must appear in the same order as they appear in the sourceBuffers attribute: video is first sourceBuffer, video media appended first 
PASS Active SourceBuffers list reflects changes to selected audio/video tracks associated with separate SourceBuffers. 
PASS Active SourceBuffers list ignores changes to selected audio/video tracks that do not affect the activation of the SourceBuffer.