CEA-608 parsing can't handle emulation prevention bytes

grabofus commented 3 years ago

Environment

[x] The MPD passes the DASH-IF Conformance Tool on https://conformance.dashif.org/
[] The stream has correct Access-Control-Allow-Origin headers (CORS)
[x] There are no network errors such as 404s in the browser console when trying to play the stream
[x] The issue observed is not mentioned on https://github.com/Dash-Industry-Forum/dash.js/wiki/FAQ
[] The issue occurs in the latest reference client on http://reference.dashif.org/dash.js/ and not just on my page
Link to playable MPD file: Can't provide a publicly available stream
Dash.js version: 3.2.2
Browser name/version: Chrome 91
OS name/version: MacOS Catalina

Steps to reproduce

Load a stream with CEA-608 caption, that has emulation prevention bytes in the SEI unit prior to the user data.

Observed behavior

The player doesn't remove the emulation prevention bytes prior to passing the data to the CEA-608 parser, this can cause an offset while reading the data leading to skipping the user data unit containing the caption on specific fragments.

Console output

[457][Protection] EME detected on this user agent! (ProtectionModel_21Jan2015) 
[459][MediaPlayer] Streaming Initialized 
[460][MediaPlayer] Playback Initialized 
[461][MediaPlayer] [dash.js 3.1.0] MediaPlayer has been initialized 
[612][DashParser] Parsing complete: ( xml2json: 8.80ms, objectiron: 0.200ms, total: 0.00900s) 
[619][TimeSyncController] Local time: Tue Jun 22 2021 16:01:24 GMT+0100 (British Summer Time) 
[620][TimeSyncController] Server time: Tue Jun 22 2021 16:01:21 GMT+0100 (British Summer Time) 
[620][TimeSyncController] Server Time - Local Time (ms): -3712 
[626][ManifestUpdater] Manifest has been refreshed at Tue Jun 22 2021 16:01:24 GMT+0100 (British Summer Time)[1624374084.706]  
[675][AbrController] [video] switch from 0 to 5/5 (buffer: 0) . 
[692][AbrController] [video] switch from 0 to 5/5 (buffer: 0) . 
[701][Stream] No text data. 
[701][Stream] No fragmentedText data. 
[703][Stream] No muxed data. 
[703][Stream] No image data. 
[717][ProtectionController] DRM: KeySystem Access Granted (com.widevine.alpha)!  Selecting key system... 
[788][BufferController][video] Init fragment finished loading saving to video's init cache 
[789][ScheduleController][video] OnFragmentLoadingCompleted - Url: https://XXXXX/init_video_4500.m4s  
[795][BufferController][audio] Init fragment finished loading saving to audio's init cache 
[795][ScheduleController][audio] OnFragmentLoadingCompleted - Url: https://XXXXX/init_audio_412.m4s  
[821][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[860][ScheduleController][video] Top quality video index has changed from undefined to 5 
[859][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[862][ScheduleController][audio] Top quality audio index has changed from undefined to 0 
[905][VideoModel] Caught pending play exception - continuing (NotAllowedError: play() failed because the user didn't interact with the document first. https://goo.gl/xX8pDD) 
[923][PlaybackController] Native video element event: loadedmetadata 
[995][ScheduleController][audio] OnFragmentLoadingCompleted - Url: https://XXXXX/media_audio_412-7756211.m4s  
[990][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[1058][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[1088][ScheduleController][audio] OnFragmentLoadingCompleted - Url: https://XXXXX/media_audio_412-7756212.m4s  
[1182][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[1185][ScheduleController][video] OnFragmentLoadingCompleted - Url: https://XXXXX/media_video_4500-7756211.m4s  
[1206][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[1299][PlaybackController] Requesting internal seek to time: 46537260.084 
[ERROR] Cannot insert 4e (N) at position 32. Skipping it!
[ERROR] Cannot insert 49 (I) at position 32. Skipping it!
[ERROR] Cannot insert 54 (T) at position 32. Skipping it!
[ERROR] Cannot insert 41 (A) at position 32. Skipping it!
[ERROR] Cannot insert 59 (Y) at position 32. Skipping it!
[ERROR] Cannot insert 49 (I) at position 32. Skipping it!
[ERROR] Cannot insert 54 (T) at position 32. Skipping it!
[ERROR] Cannot insert 4c (L) at position 32. Skipping it!
[ERROR] Cannot insert 4c (L) at position 32. Skipping it!
[ERROR] Cannot insert 4d (M) at position 32. Skipping it!
[ERROR] Cannot insert 52 (R) at position 32. Skipping it!
[ERROR] Cannot insert 50 (P) at position 32. Skipping it!
[ERROR] Cannot insert 41 (A) at position 32. Skipping it!
[ERROR] Cannot insert 50 (P) at position 32. Skipping it!
[ERROR] Cannot insert 45 (E) at position 32. Skipping it!
[ERROR] Cannot insert 56 (V) at position 32. Skipping it!
[ERROR] Cannot insert 49 (I) at position 32. Skipping it!
[ERROR] Cannot insert 2c (,) at position 32. Skipping it!
[ERROR] Cannot insert 20 ( ) at position 32. Skipping it!
[ERROR] Cannot insert 42 (B) at position 32. Skipping it!
[ERROR] Cannot insert 20 ( ) at position 32. Skipping it!
[ERROR] Cannot insert 4e (N) at position 32. Skipping it!
[ERROR] Cannot insert 20 ( ) at position 32. Skipping it!
[ERROR] Cannot insert 4d (M) at position 32. Skipping it!
[ERROR] Cannot insert 2c (,) at position 32. Skipping it!
[1613][ScheduleController][video] OnFragmentLoadingCompleted - Url: https://XXXXX/media_video_4500-7756212.m4s  
[1629][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[5577][ScheduleController][video] OnFragmentLoadingCompleted - Url: https://XXXXX/media_video_4500-7756213.m4s  
[5674][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[6021][AbrController] [video] switching from throughput to buffer occupancy ABR rule (buffer: 12.150). 
[6046][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[6439][ScheduleController][audio] OnFragmentLoadingCompleted - Url: https://XXXXX/media_audio_412-7756213.m4s  
[6485][ProtectionController] DRM: Ignoring initData because we have already seen it! 
[7850][PlaybackController] Native video element event: play 
[7879][PlaybackController] Native video element event: playing 
[ERROR] Cannot insert 41 (A) at position 32. Skipping it!
[ERROR] Cannot insert 4e (N) at position 32. Skipping it!
[ERROR] Cannot insert 52 (R) at position 32. Skipping it!
[ERROR] Cannot insert 4f (O) at position 32. Skipping it!
[ERROR] Cannot insert 56 (V) at position 32. Skipping it!
[ERROR] Cannot insert 41 (A) at position 32. Skipping it!
[ERROR] Cannot insert 44 (D) at position 32. Skipping it!
[ERROR] Cannot insert 41 (A) at position 32. Skipping it!
[ERROR] Cannot insert 54 (T) at position 32. Skipping it!
[ERROR] Cannot insert 48 (H) at position 32. Skipping it!
[ERROR] Cannot insert 48 (H) at position 32. Skipping it!
[ERROR] Cannot insert 41 (A) at position 32. Skipping it!
[ERROR] Cannot insert 43 (C) at position 32. Skipping it!
[ERROR] Cannot insert 4f (O) at position 32. Skipping it!

Trace headers of a segment with ffmpeg

[trace_headers @ 0x7fc48241a080] Access Unit Delimiter
[trace_headers @ 0x7fc48241a080] Supplemental Enhancement Information
[trace_headers @ 0x7fc48241a080]   Picture Timing
[trace_headers @ 0x7fc48241a080]   User Data Registered ITU-T T.35
[trace_headers @ 0x7fc48241a080] Slice Header

Expected behavior

Player should be able to parse CEA-608 captions.

grabofus commented 3 years ago

I have a patch for the issue in a fork of DASH.js, happy to raise a PR if this issue is being worked on by anyone else.

https://github.com/DiceTechnology/dash.js/tree/fix/cea608-emulation-prevention-byte

dsilhavy commented 3 years ago

yes please do a pr against the latest status of the development branch. would also be great if you can provide a sample stream to verify.

dsilhavy commented 3 years ago

@grabofus Can you provide a PR for this?

grabofus commented 3 years ago

Sorry, I've been busy with other stuff lately, I'll try to PR it this week. I haven't been able to get a stream I can share where this issue is reproducible though

stale[bot] commented 2 years ago

This issue has been automatically marked as stale because it has not had recent activity. However, it might still be relevant so please leave a short comment if it should remain open. Otherwise the issue will be closed automatically after two weeks. Thank you for your contributions.

grabofus commented 2 years ago

Issue still exists

stale[bot] commented 2 years ago

This issue has been automatically marked as stale because it has not had recent activity. However, it might still be relevant so please leave a short comment if it should remain open. Otherwise the issue will be closed automatically after two weeks. Thank you for your contributions.

dsilhavy commented 2 years ago

unstale

stale[bot] commented 2 years ago

This issue has been automatically marked as stale because it has not had recent activity. However, it might still be relevant so please leave a short comment if it should remain open. Otherwise the issue will be closed automatically after two weeks. Thank you for your contributions.

stale[bot] commented 2 years ago

This issue has been automatically closed because no further activity occurred. If you think this issue is still relevant please reopen it or contact @dsilhavy. Thank you for your contributions.

dsilhavy commented 4 months ago

Fixed in #4522

Dash-Industry-Forum / dash.js