I've mentioned this in another thread but after some more experience, thought I'd put together what I've found. The problem: 1. Some MKVs I've backed-up from 4K discs with Dolby Vision suffer from an image freeze during the end credits. 2. Audio continues to play but the image freezes and occasionally closes the file. 3. It's possible to restart the file again, "rewind" it to just before the freeze happened and for the file to play correctly. 4. I've never noticed this happening on 2K MKVs backed up from BD or 4K MKVs without Dolby Vision. 5. It hasn't happened on every 4K MKV with Dolby Vision - some play perfectly. My back-up and playback process: 6. All my MKVs are backed-up using MakeMKV from the disc that I've purchased. 7. MakeMKV doesn't throw any errors during the backup so I'm confident the resulting MKV is bit-for-bit identical with what was on the disc (spinning the disc doesn't reproduce the freeze error, so it's not an error on the disc). 8. I haven't messed with the resulting MKV in any way (no subtitle removal or anything at all). 9. The MKV is copied to 2 4TB Western Digital HDD's so I have a backup of the backup. Either HDD can reproduce the freeze error, so it's not a faulty HDD. 10. Playback of the MKV via the USB3 port(s) on the Z9X either directly (no external power) or via a powered USB hub can reproduce the freeze error. Offending 4K Dolby Vision files: 11. 2001: A Space Odyssey (1968): I stopped (I pressed Stop, not Pause) this one just before Frank went out to reinstall the faulty unit and noticed some frame-skipping when I resumed it. After two reboots, it started playing correctly again. 12. Scream (1996): End credit image freeze. 13. Apocalypse Now Redux (1979): About 15 minutes before the end, the image-freeze happened during the movie. After a file stop and restart, it played correctly. 14. Awaken (2021): End credit image freeze. This has happened on 2 separate viewings in the same part of the end credits. 15. The Texas Chain Saw Massacre (1974) - Second Sight's 4k release: After I stopped the movie around midway, I resumed it only to have the image freeze a couple of times. After a reboot, it played through the previously "freeze" sections fine. Why? 16. From everything above, I'm guessing it's something related to the Dolby Vision info in the MKV that the Z9X struggles with after a period of playing most of the file. As mentioned though, the MKV can be restarted, "rewound" to before the freeze and will play through it fine, so it's not a dud part of the file or HDD. 17. It could also be a HDD stutter. However, as mentioned in 14 above, it's happened on 2 separate viewings in the same part of the end credits on 2 different HDDs which would suggest it's a file-reading problem. I know most don't sit through the end credits so this may have gone unnoticed but I'd be interested in any possible explanations you may have and/or similar experiences + any corrective action you could recommend. Thanks
