Starting point for allowing the download of next 3 chunks instead of just nextChunk to be played?

[adney11]

Hi All,

Can someone help me identify where I can modify the player code such that it requests and stores the next 2 or 3 chunks [as per the specified list of requested bitrates] instead of just downloading the next to be played chunk?
Of course, incase when playing the next chunk, a different bitrate is required, I want to make a request for the correct bitrate chunk - or even in this case, the next 3 chunks.

I see a getNextFragment in ScheduleController.js - but I'm not sure how to proceed from here.
Any pointers would be appreciated.

Please let me know if you need more context from my end!
Thank you.

[dsilhavy]

Are you trying to download multiple segments in parallel?

Otherwise what you described sounds like a buffer setting. dash.js has certain buffer targets, see here: https://reference.dashif.org/dash.js/nightly/samples/buffer/buffer-target.html .

Also note that for live streams the segments become available over time compared to VoD where all segments are available at playback start.

[adney11]

Hi @dsilhavy,

Thank you for your response - from my understanding, the buffer target sets the trigger for fetching the next chunk? How would I specify the bitrates for these?

Detailed Context:

I actually want to "pre-download" the chunk i+1 and i+2 when downloading chunk i.
These extra chunks will be downloaded for bitrates predicted at the time of requesting chunk i at specified bitrate.
The goal is to maintain a prefetch buffer, and in case the prefetched chunk's bitrate for the next-to-be-played chunk is not optimal anymore, then refetch the correct chunk with the corrected bitrate.

To rephrase: I want to extend the current ABR algorithm to give "list of bit rates" corresponding to the bitrates of the next, next to next and the chunk after that. How should I go about fetching multiple chunks instead of making a GET request for only one chunk?