"If last decode timestamp for track buffer is unset and there is a coded frame in track buffer with a presentation timestamp less than or equal to presentation timestamp and presentation timestamp is less than this coded frame's presentation timestamp plus its frame duration, then run the following steps:"
I suggest defining the "presentation interval" of a frame somewhere and replacing the above with:
"If last decode timestamp for track buffer is unset and presentation timestamp falls within the presentation interval of a coed frame in track buffer, then run the following steps:"
"Presentation interval" would be defined as follows:
"The presentation interval of a frame is the time interval from the presentation time of the frame to the presentation time of the frame plus its frame duration."
We might want to define it as the open range which includes the start value but not the end value (i.e. [ p, p + d ) for p = presentation time, d = frame duration).
Added presentation interval definition and updated a few other places in the text where this term simplifies the text.
I also added a definition for "coded frame duration" and updated various places in the text to explicitly use this term since frame duration was not actually defined anywhere but was used in several algorithms.