KinoAmp 0.51

Hello,

a new version of KinoAmp is available from:

http://www.riscos-digitalcd.net/image/kinoamp/kinoamp.htm

Changes:

• Add neon version of (bi)linear interpolation in 16M colors.
• Read DVD subtitles. Limitation: colors info not known.
• Drop VIDEO_TS folder to read main VOBS of DVD as a single one.
• Add pane flag to toolbar to prevent RISC OS from continuously attempting to bring the window before its toolbar while dragging the title bar.

Sounds like a nice update! Question/suggestion arriving from the DVD related features… does KinoAmp (or could it) support MPEG2 inside MKV containers? I ask because that’s what you (probably?) get from something like MakeMKV from a DVD. Otherwise I’d imagine CSS issues?

I Never thought I’d see MPEG2 encapsulated into another container. If someone can point some examples of MKV or AVI encapsulated MPEG2 files, I would be interested to had support for them.

Regarding DVDs, basically everything remains to be done: menus, chapters, multi-angle or even a normal replay (in theory the VOBs could contain the chapters in any order). For DeCSS, well I have not even the fainted idea how to read encrypted sectors from CDFS.

I’m pretty sure that it can’t be done via CDFS. Decrypting VOBs in the ‘intended’ fashion demands a length sequence of low-level ATAPI commands and responses; exchanging DVD-specific commands with the drive, authenticating with it in order to establish the drive region code, retrieve the disc key, and then the scrambled title key which is used to decrypt the CSS-encrypted VOB file. Cino employs a couple of prototype modules ‘DVDFS’ and ‘DVDATAPI’ which sit alongside CDFS and talk to the ADFS module to issue ATAPI commands.

Online sources suggest that it is now possible to decrypt CSS-scrambled VOB files without the title key, and on a feasible timescale, by using a rather brute force attack on a fast desktop PC. I know nothing more about that, however.

For DeCSS to work, you read the files in a standard way and then decrypt them with DeCSS. CDFS knows nothing about it, the drive knows nothing about it, everything is supplied encrypted.

Adrian’s way is the “official” way for DVD playback without the decryption hack that is DeCSS.

For later CDFS versions (RISC OS 5.10 I think), there is the CD_SCSIUserOp interface which should work for ATAPI drives recognized by CDFS – early versions of CDBurn used that for the IYONIX before switching to directly drive via ADFS.

For DeCSS to work, you read the files in a standard way …

I remember that when I tried to copy a DVD to my HD to play with it later, CDFS popped an “Illegal target” error on the encrypted VOB files so I don’t think there is a standard way.

You’ll find various implementations at http://www.cs.cmu.edu/~dst/DeCSS/Gallery/ ¹ which tries to underline the absurdity of DeCSS printed on a T-shirt being protected speech and as an executable (of the same thing) being evil incarnate.² The best bit was the legal filing against DeCSS that contained full source code and was originally submitted unrestricted (it’s now sealed, but not after World+Kitten took a copy).

Legality? All over the place and untested in the EU. Look at libdvdcss. Hell, it could be argued that you’re using the interoperability clause to get such DVDs working on RISC OS ³…

¹ I am posting the URL as it’s literally the second link in a Google search, after a Wikipedia article and some “people also search for” rubbish.

² So you might want to consider geoblocking the US? The horse is so far out of its stable that it got old and died, but the MPAA is utterly irrational.

³ Which would be a Good Thing.

an “Illegal target” error on the encrypted VOB files

It’s perhaps worth pointing out that computers pay more attention to the content of DVDs, more than the somewhat lackadaisical behaviour of real DVD players.
So if you’re using a computer, you’ll be faced with all sorts of bull such as sectors with broken checksums, or my personal favourite a TOC that contains a hundred of entries of utter rubbish. Sometimes the TOC is valid but the offsets are gibberish (I guess real DVD hardware clips oversized stuff, but computers don’t and get tripped up?).

Usually, with Handbrake ¹, ripping a DVD “just works”. Sometimes I need to play it in VLC to get the title ID of the film to get Hardbrake to perform a title scan (for intentionally broken TOCs). Sometimes the drive just tells me there’s no disc inside because the low level stuff is so messed up that the drive just can’t recognise it (yet it starts up on a hardware DVD player).

You may need to find a way to get data from the drive below the level of CDFS, but just be aware, the more expensive the production, the freakier the attempts at copy protection are likely to be. And such protection never did make a dent on piracy, it’s mostly there so they can enforce region coding on the hapless consumers…

¹ I pay money for a DVD, I’ll watch it on the device of my choosing.

Adrian’s way is the “official” way for DVD playback without the decryption hack that is DeCSS.

That’s not quite correct. Cino also depends upon a DeCSS module which is little more than a compilation of the public domain DeCSS code; DeCSS includes some player keys gleaned from a software DVD player (the hacking involved) and also perform the unscrambling/decryption. But still, the title key required for performing the unscrambling is stored on the DVD as ‘out-of-band’ data, not within the regular disc sectors; nor within the VOB or DeCSS source.

an “Illegal target” error on the encrypted VOB files

That’s right, unless you’ve gone through the region coding and authentication steps that I outlined.

Hm. I did simple sector copies of various DVDs on RISC OS without any noticeable problems. Maybe I accidentially never tried a true CSS protected DVD?

Of course, if you rely on CDFS on interpretation of the disc’s content, any error is to be expected, especially with DVD drives, so if you want to copy VOBs from a DVD via CDFS I wouldn’t be surprised if it fails. I remember studying the CDFSSoftATAPI driver source which did a staggering amount of magic to try to support Mode 2 CDs – and this lead to failure reading ANY simple DVD, because it broke simple 1-data-track “Mode 1” DVDs…

Concerning Region Codes: long time ago, I knew a lot more about it…but IIRC, all modern drives use RPC-2, which means that the drive has a “default” region which can be changed only a limited amount of times. The drive does the whole management, it is basically firmware hardcoded.

I think the software side is only in the box when RPC-1 is active.

But I have zero experience in practice, since I got stuck in trying to write those many damned DVD-+whatever variants…

I Never thought I’d see MPEG2 encapsulated into another container. If someone can point some examples of MKV or AVI encapsulated MPEG2 files, I would be interested to had support for them.

Here is something sufficiently old that the copyright’s expired (at least here in NZ; I’m not sure what the rules are overseas). If it’s an issue over there then let me know and I’ll remove it.

Should probably warn people that it’s 1.04GiB. ;-)

Monty Python in English, Hungarian, and Polish.

On Android, VLC was able to play the video. MAX Player didn’t recognise the video format. I started streaming it directly, as my internet is too slow to download something that large on a whim…

Sorry about the lack of description; was too busy thinking about the disclaimer!

If you want a real mystery, try to figure out why it has Hungarian and Polish options given that it’s region 4!

Drop VIDEO_TS folder to read main VOBS of DVD as a single one.

Works perfect and if I set the right audio channel, it will not lost..

Many thanks!