It turned out some of the files were encoded with h.264 level 5, which appears to be incompatible with the PS3. This is relatively easy (and quick) to fix:

1. With Yamb split out the audio and video streams
2. Use H264info to convert the video to Level 4.1 (don’t touch the other options)
3. Recombine audio and video using Yamb (make sure you set the correct framerate for the video stream, or it will be out of sync)

Whilst Yamb seems to work extremely well, the UI suffers from appalling glitches when navigating (mainly due to button placement and having to go back and forth to split and join), so be careful not to overwrite any files if you batch convert.

For a better explanation of H264 levels see this page, and the H264info switches are described toward the bottom here.

1. Uninstall previous TVersity, ffdshow, codecs etc
2. Reboot
3. Install Tversity, ffdshow
4. Install Haali Matroska Splitter
5. Set the TVersity service to log on using a local admin account.

I used Zoom player to verify Haali is working, then tested on the PS3. It would appear that Haali needs to run with admin privilege.

For best performance, update the PS3 profile in profiles.xml to transcode to mpeg2. At 1280×720 over a 100 base T network the default of mpeg16 saturates my bandwidth in some cases. This is the relevant part of the config file:

<transcodeTarget audio="audio/x-wav" video="video/mpeg2" photo="image/jpeg"
                         onlineAudio="audio/mpeg" onlineVideo="video/mpeg2" onlinePhoto="image/jpeg"
                         adjustReadStartPos="false" audioFailFutureSeek="false" videoFailFutureSeek="true" />

I’m using Vista x64 with UAC disabled, your mileage may vary on other configurations.