WD TV LIVE persistent subtitle issues

[vihena]

Wow... that's terrible, and unfortunate. This device looks like it's exactly what I'm looking for too - playing local media, with good support for youtube and other premium content without the bloat.

But this subtitle issue is enough of a deal breaker that I'll probably end up spending 3x more to get an HTPC with XBMC. Really unfortunate.

[Enigma316]

Since it's apparent WD has no intention of ever fixing this do you guys know of a HD media player that fully supports A.S.S. subtitles? I watch a lot of subbed anime and foriegn films, so I could use a media player that is able to properally display the subs. I've payed hundreds of dollars on WD products only to be disapointed every time. They're great when it comes to prettty much every format except MKV which just so happens to be my most played format.

[Techflaws]

Actually pixelpower and me have been contacted by WD to provide them with files demonstrating the bugs listed in this thread and we happily complied. Of course this does not mean those bugs will be fixed. However, if you really want to get tips on other players, please start your own thread cause I want this one to stay on topic.

[Enigma316]

That's good to hear. I've always loved WD products and I would love them even more if the support for subtitles would get better.

[mjuhasz]

"-dropouts: External/internal idx/sub with more than 1 stream show irregular dropouts of certain items."

While converting some of my dvds to mkv with Handbrake I thought I ran into this bug: certain subtitles from an idx/sub file did not show up no matter if I muxed them into the mkv or used them as external files. Some sentences were missing and it was very annoying to watch the movie with these irregular dropouts.

Those subtitles that did not show up had no end time set and WDTV Live (with firmware 1.05.04_V) does not display them from an idx/vob file. The funny thing is that it does display them from within a dvd iso.

I fixed the subtitles with BDSup2Sub: simply opened the idx/sub file, and saved them after seeing warnings "WARNING: Invalid end sequence offset -> no end time"  As an external subtitle it works fine now (as internal one it still has the palette bug with the colors are messed up therefore I use externals).

[Techflaws]

Mmh, what end time are you talking about? An idx usually looks like this:

timestamp: 00:01:12:840, filepos: 000000000
timestamp: 00:01:15:440, filepos: 000001800
timestamp: 00:01:17:000, filepos: 000002800
timestamp: 00:01:19:160, filepos: 000003800


So where is the endtime of each item listed?

Tests so far suggest that the dropouts stem from AutoGK. Do you know what tool Handbrakes uses to extract the subs from the ISO?

[mjuhasz]

The idx snippet you pasted contains the byte offsets for each subtitle frame and its timing.

In my case the problem was with the sub file. I figured (it was just a hunch) that there is some inconsistency in the binary stream (the sub) extracted from the dvd. The sub is the raw Packetized Elementary Stream (PES) dumped from the dvd and it is binary hence hard to inspect and I was not able to find any good specification about it.

Off the top of my head I remembered that I read somewhere that WDTV had issues in the past with (bogus?) binary sub streams. So I just parsed the binary with the BDSup2Sub and that proved my right: "Invalid end sequence offset -> no end time". The program fixes the invalid end offset while importing the sub file. Then it can be exported and WDTV is happy to show the previously missing subtitles as well.

I checked a few other sub files extracted with Handbrake and all are fine. It my be an incorrectly authored dvd and other players (even WDTV in dvd mode) are more robust and handling these errors gracefully.

Without the specification I cannot tell whether the END command in the subtitle frame is mandatory or optional but it would be nice if WDTV could recover even if it's missing. It's just a matter of setting the end offset to the size of the control header in the frame while parsing.

[Techflaws]

Nice catch. Gonna check out if this has any effect on my subs done with AutoGK. Concerning sub specs, I've only found this so far (check out MPEG Quick Reference > "Pack Headers" and "Packetized Elementary Stream Headers").

[mjuhasz]

"Internal Vobsubs (idx/sub) are messed up, apparently some colors of the palette are ignored/replaced."

I spent a couple of hours on this and found the bug. The subframe in a subtitle stream has 4 colors. Each of those have an index that refers to one color in the palette and each has an alpha (opacity) value. The bug is that WDTV sets the alpha value to zero for the 4th color hence it's always transparent. If the 4th color is assigned to the outline then the subtitle seems to have no outline. If it's assigned to the pattern then you can "see through" the characters (they only have outline), etc.

As a workaround the subtitle colors can be swapped in a way that an already transparent color gets the last index. There is always one - the background color. This workaround does not change the look of the subtitle at all other than the case where it's embedded and played on wdtv.

I did not find any tool that could do this index swapping so I have modified the bdsup2sub to have an option to export idx/sub with this wdtv workaround. It finds a transparent color and swaps it with the 4th color that wdtv already interprets as fully transparent (and does the same with the alpha values and the palette references). BTW, running the subtitle through bdsup2sub works around the invisible subtitle bug as well that I mentioned earlier: it sets the end time for the subtitles with indefinite duration.

PS: I have not published the modified bdsup2sub because I have to check the license restrictions or contact the author first.

[TonyPh12345]

Wow.  Fantastic bit of troubleshooting!