Issues with Adaptive streaming
I have recently observed couple of issues with player when playing adaptive bitrate hls. I am currently using three renditions - 130kbps , 250kbps , 500kbps.
1) lot of times buffering icon appears when player is switching between two bitrates. I observed that when my bandwidth is somewhere between two renditions ie every alternate request was of different rendition something like - seg1_250 , seg2_500 , seg3_250 , seg4_500 etc. here i was also seeing some of the calls being repeated for same segment for eg two calls like seg1_250 and seg2_500 . and while these things were happening in background users were seeing loading spinner lot of times. And once user clicked on a bitrate say 250kbps the playback was smooth from that point of time. If my understanding is correct player should download a chunk and add it to buffer in advance and at any time there should be sufficient data in buffer for playback given that my bandwidth is fairly higher than the lowest bitrate. But the behaviour which i observed indicated that on addition of every chunk , old buffer was getting flushed if prev bitrate was different. This was flash fallback hls player on desktop chrome. Is there a configuration option which dictates buffer size when using http streaming ? i am aware of rtmp playback buffer.
2) second issue i observed when i switched from a fixed bitrate to "Auto" option while playback. here i observed that sometimes player was sending requests for some old video chunk which were not present on server since it was live stream. for example you can see in the image attached in link player was playing seg_129 at some point but suddenly player started sending request for segment number 114. and response for which was 404. and this call was repeating a lot times before finally player recovered and started playing normally. But this also resulted in user seeing the buffering icon.
PS - all this was done on live stream.