getMeanAudioFormatBitrate() API from PlaybackStats return -1 for HLS Content

[pmaurya74]

HI There,
I am using getMeanAudioFormatBitrate() API from PlaybackStats that return -1 for HLS Content.
But return correct value for progressive mp4 content.

Other than above API i used below APIs as well for HLS content (AV or Audio Only), but all returns -1 for audio bit rate .
1)onDownstreamFormatChanged. (from audio track format)
2)onLodeStared
3)onLoadCompleted
4)audioTracks.get(0).format.bitrate

Device information:
ExoPlayer version number - ExoPlayerLib/2.12.3-1.0-dev
Android version - Android 7.1.2(Amazon/mantis/mantis:6.0/NS6280/3236N:user/amz-p,release-keys)
Android device -Fire TV Stick 4K

HLS Content Logs Analysis for -1 audio bitrte:
2021-07-10 17:14:56.970 7639-7874/com.tivo.exoplayer.demo I/MediaCodecLogger: 7639.SW.audio.mp4a.bitrateInKbps = 61
2021-07-10 17:15:08.991 7639-7880/com.tivo.exoplayer.demo I/MediaCodecLogger: 7639.4K.HW.video.avc Resolution change from 0x0 to 1280x720 took = 0
2021-07-10 17:15:09.005 7639-7880/com.tivo.exoplayer.demo I/MediaCodecLogger: 7639.4K.HW.video.avc.bitrateInKbps = 688

021-07-10 17:15:12.713 7639-7639/com.tivo.exoplayer.demo I/ManagePlaybackMetrics: session end stats, URL: null stats: {"avgBandwidthMbps":3.103492,"initialPlaybackStartDelay":5811,"totalTimeMs":23533,"totalPlayingTimeMs":5723,"totalElapsedTimeMs":23533,"videoFramesDropped":0,"totalRebufferingTimeMs":11987,"profileShiftCount":2,"rebufferCount":1,"avgVideoBitrate":4.079073,"endedFor":"USER_ENDED","avgAudioBitrate":-1.0E-6,"totalTrickPlayTimeMs":0,"timeInFormats":{"0 - 720x480@2300000":2034,"2 - 1280x720@5060000":3689}}

I will send HLS url in mail . for that URL MediaCodecLogger is able to get audio bit rate but getMeanAudioFormatBitrate or other API returns -1 .

Progressive MP4 content Analysis:

3:44.366 7639-7639/com.tivo.exoplayer.demo I/ManagePlaybackMetrics: session end stats, URL: null stats: {"avgBandwidthMbps":-1.0E-6,"initialPlaybackStartDelay":6428,"totalTimeMs":10590,"totalPlayingTimeMs":4149,"totalElapsedTimeMs":10590,"videoFramesDropped":0,"totalRebufferingTimeMs":0,"profileShiftCount":0,"rebufferCount":0,"avgVideoBitrate":-1.0E-6,"endedFor":"USER_ENDED","avgAudioBitrate":0.032,"totalTrickPlayTimeMs":0,"timeInFormats":{}}

I will send url in mail but here audiobitrate value is proper for progressive mp4 url.

Request you to fix this issue in getMeanAudioFormatBitrate API for HLS content or let us know by any other callback or API we can get proper audio bitrate.
I will other url and content information in mail to dev.exoplayer@gmail.com with issue number subject.
BugReport:

bugreport-NS6280-2021-07-10-17-26-58.zip

.

[pmaurya74]

I have send url and content information in mail to dev.exoplayer@gmail.com with issue number subject.
Issue #9175

[christosts]

Thank you for reporting this.

PlaybackStats.getMeanAudioFormatBitrate() returns -1 (=> C.LENGTH_UNSET) because the player cannot derive accurate audio bitrate information from the HLS playlist.

According to the HLS spec, bitrate information can be derived from the BANDWIDTH attribute of the EXT-X-STREAM-INF tag, however in most cases this refers to the aggregate bitrate of a stream and this includes video and audio. This same rule applies when audio and video are either muxed or demuxed (the playlist you provided has audio muxed with video). Considering that video bitrates are typically much higher than audio, the player assumes that BANDWIDTH information regards video bitrate and not audio.

The player uses the BANDWIDTH information for audio-only HLS playlists to derive audio bitrate. However, there was a bug and the audio bitrate was not propagated to PlaybackStats for audio-only HLS playlists. This is fixed in 4b1609d and will be included in the next release, 2.15.0.

The link provided for the progressive case: the audio stream has ICY metadata which clearly point to the audio bitrate and the player uses those correctly.