MYST: Unable to play certain videos: Cannot convert high color video frame to 8bpp!

[hansejo]

Recently played through the original 1994 Windows version of Myst. I found two videos which would play the audio, but no video. When this would happen the log would be spammed with:

WARNING: Cannot convert high color video frame to 8bpp!

The two videos in question (unmodified from my CD copy):

5757fe67077ae3d418737eb4472f8048  qtw/selen/forwe0.mov
2b29368fda60e11cec13e93ee9aac17b  qtw/channel/monsmsg.mov

ScummVM version (compiled from git via AUR package):

ScummVM 2.6.0git (May 14 2022 00:39:06)
Features compiled in: TAINTED Vorbis FLAC MP3 ALSA SEQ sndio TiMidity RGB zLib MPEG2 FluidSynth Theora AAC A/52 FreeType2 FriBiDi JPEG PNG GIF TTS cloud (servers, local) TinyGL OpenGL (with shaders) 

Linux version:

Artix Linux 5.17.6

I will attached mediainfo and the full log

[digitall]

Replicated with my version of Myst MPC on Linux x86_64 with latest dev master. The MD5sums of the two videos match my version.

[digitall]

Have added patch for the cinepak decoder from IRC by antoniou79 which resolves this problem, though unclear if this is the "right" solution?

[antoniou79]

I've opened a PR with the above suggested fix so that it can be properly tested/reviewed:
​https://github.com/scummvm/scummvm/pull/4157
Edit: sluicebox has provided a PR with the correct solution to this issue.

[antoniou79]

After sluicebox noted that this bug could be due to a regression caused in November 2021 to quicktime decoder, and that his own today PR addresses the issue, I can confirm that his approach is the correct one, since it works flawlessly (my suggestion results in some black artifacts at the start of the video).

For reference sluicebox's PR is here:
​https://github.com/scummvm/scummvm/pull/4156

[sluicebox]

Fixed in: ​https://github.com/scummvm/scummvm/commit/69662ee9a44ef8124ff282c716422e67f06f282a

Sorry for breaking Myst!