HLS-FMP4 DTS:X Profile 2 Streams are missing first 2 seconds during Tunnel mode (Direct) Playback due to timestampAdjuster in FragmentedMp4Extractor.java

[cedricxperi]

Version

Media3 main branch

More version details

Devices that reproduce the issue

All Android TV with DTSX Decoder. E.g. Xiaomi Q2 55"

Devices that do not reproduce the issue

None.

Reproducible in the demo app?

Yes

Reproduction steps

• Add the following URL to media.exolist.json: https://secured.streamdts.com/dtsx/dtsx/hls/fmp4/callout/index.m3u8
• Enable Tunnel mode
• Playback the stream and observe that the first 2 seconds are skipped.
• Disable Tunnel mode
• Playback the stream and observe that playback is now ok.
• Playback is also ok with the follow DASH stream in tunnel mode. And I have verified that for DASH, there is no timestamp adjustments that are going on: https://secured.streamdts.com/dtsx/dtsx/dash/callout/index.mpd

NOTES: HLS-FMP4 DTS:X Profile 2 Streams are missing first 2 seconds of audio during Tunnel mode (Direct) Playback due to timestampAdjuster in FragmentedMp4Extractor.java.

• This only happens for Tunnel mode playback with DTS:X audio playing back via Direct Passthrough.
• This does not happen when playing back through MediaCodec DTSX Decoder.
• When the following lines (around line 1538) in FragmentedMp4Extractor.java are commented, the playback seems ok. if (timestampAdjuster != null) { sampleTimeUs = timestampAdjuster.adjustSampleTimestamp(sampleTimeUs); }
• FYI, DTS:X Profile 2 audio codec has a sync and non-sync frame concept. So once the first sync frame is lost, the whole section of audio cannot be decoded properly until the next sync frame can be located. In this stream, the sync interval is 2 seconds. It correlates with the 2 seconds lost in the beginning.
• What does timestampAdjuster do exactly? When are these adjustments to the presentation time stamps required?
• Is the presentation time stamp adjustments necessary when playing back via Direct Passthrough?
• How can we resolve this issue more gracefully?

Thanks!

Expected result

Playback does not skip the first 2 seconds.

Actual result

Playback skipped the first 2 seconds.

Media

HLS-fMP4 stream. First 2 seconds lost during playback in tunnel mode: DTS:X 5.1.4 - HLS fMP4: https://secured.streamdts.com/dtsx/dtsx/hls/fmp4/callout/index.m3u8

DASH stream with no playback issues: DTS:X 5.1.4 - DASH: https://secured.streamdts.com/dtsx/dtsx/dash/callout/index.mpd

The PTS values are the same in both streams.

Bug Report

• [ ] You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.

[cedricxperi]

@tianyif If you have the bandwidth, kindly have a look at this issue above and let me know if it rings any bell. Thanks!

[cedricxperi]

@tianyif Just checking if you have any updates for me on this issue. Thanks.

[cedricxperi]

@tianyif We just received notice that this issue is affecting some Android TVs running Disney+ apps. Kindly look at this issue. It is highly likely that any audio codec with a Sync Frame concept delivered with HLS-fMP4 will be affected. Thanks.