How common is [log] > [tsdemuxer]: AAC: align PTS for overlapping frames by -23?

[lpommers]

What do you want to do with Hls.js?

I'm just curious what leads to so many logs from the tsdmuxer regarding audio frames? It happens quite frequently throughougt this video (and several other test videos). The audio in the file is just the source audio of the video file, not an alternative audio track.

Is this most likely related to how I've created my HLS playlist segments via ffmpeg?

[log] > [tsdemuxer]: AAC: align PTS for overlapping frames by -23

Demo Stream

https://hls-js-dev.netlify.app/demo/?src=https%3A%2F%2Fembed-ssl.wistia.com%2Fdeliveries%2F7e4973cf750b78e0de0728c30588a448d167dcfd.m3u8&demoConfig=eyJlbmFibGVTdHJlYW1pbmciOnRydWUsImF1dG9SZWNvdmVyRXJyb3IiOnRydWUsInN0b3BPblN0YWxsIjpmYWxzZSwiZHVtcGZNUDQiOmZhbHNlLCJsZXZlbENhcHBpbmciOi0xLCJsaW1pdE1ldHJpY3MiOi0xfQ==

[robwalch]

If you disable the worker the log messages link directly to the source outputting the log messages:

https://github.com/video-dev/hls.js/blob/v1.0.4/src/demux/tsdemuxer.ts#L1000

aac overflow happens when an MPEG-2 TS PES packet with AAC data contains an incomplete AAC frame:

  // We are at an ADTS header, but do not have enough data for a frame
  // Remaining data will be added to aacOverFlow

If the next pack picked up where that left off we'd be fine, but instead, it seems that hls.js is finding packets with PTS that start before the last set of valid AAC frames ended.

Maybe you can use something like DVB Inspector to confirm this or show that hls.js's ts demuxer is in error.

[robwalch]

@lpommers, I looked into this in relation to #3834. Even with the changes in #3926 the decode error persists in browsers running on Apple OSes with ARM processors.