[mythtv-users] Ticket 11377 was: Region free DVD player?

[Richard Hulme]

On 03/04/14 20:18, faginbagin wrote:
> On 4/3/2014 3:49 AM, Stephen Worthington wrote:
>> On Wed, 2 Apr 2014 21:39:55 -0500, you wrote:
>>
>>> On Wed, Apr 02, 2014 at 05:51:31PM -0400, faginbagin wrote:
>>>> On 4/2/2014 4:09 PM, Eric Sharkey wrote:
>>>>> On Wed, Apr 2, 2014 at 3:36 PM, faginbagin <mythtv at hbuus.com> wrote:
>>>>>> Is use of MythTV as a region free DVD player supported?
>>>>>>
>>>>>> If it is, I will be posting an issue I've encountered. If it isn't, I'll keep it to myself.
>>>>>
>>>>> Officially this is not a MythTV issue.  MythTV does not itself support
>>>>> decryption of encrypted media.  If you're using MythTV with third
>>>>> party libraries that do provide such things, you should not seek
>>>>> support for that on this list.  I believe that's the party line here.
>>>>>
>>>>> Eric
>>>>
>>>> Hypothetically speaking:
>>>>
>>>> What if I have done as *I think* jedi suggested, separated the media from the content outside of mythtv and now have content that is not encrypted and plays in vlc and mplayer but not in mythtv? Is discussion on the list still off limits?
>>>>
>>>> What if I figure out and fix the problem? Should I submit a patch or keep it to myself?
>>>
>>>      I don't recall any point in time when playing video with a differing frame
>>> rate or frame size was any kind of problem on a computer. Computers have pretty
>>> much always had arbitrary setups likely to not match the local TV standard.
>>>
>>>      I play stuff from the other side of the pond all the time. Some of the
>>> stuff I have is just obscure ethnic material and other stuff is just items that
>>> are hard to find or expensive in my local region.
>>
>> There certainly are some things that will not play in MythFrontend -
>> especially if you are using VDPAU or VAAPI.  I have a test file here
>> that does not play properly with full VDPAU:
>>
>>     http://www.jsw.gen.nz/mythtv/Ondine_clip.mpg
>>     (49,498,116 bytes)
>>
>> This is a clip from one of my mother's PAL ballet DVDs.  It plays fine
>> in mplayer, even when mplayer is using VDPAU.  It does play in
>> MythFrontend if the decoding is done by the CPU and the rest by VDPAU.
>> The problem is not something to do with frame rates or frame sizes (it
>> is a standard DVD format).  I have run across a number of DVDs made
>> from older source material that have the same problem as this one -
>> the video just gives occasional flashes of partial valid frames, but
>> most of the time is just moving coloured blobs on a grey background.
>>
>> Very old Apple Quicktime .mov files also cause problems, and older
>> .wmv files will often play but will not be able to skip forward or
>> backwards (they restart playing at the beginning again if you try to
>> skip).  The .wmv files play fine in mplayer, but the old .mov files
>> even defeat it.
>
> After my last post yesterday, I finally figured out the problem. It wasn't because it's a region 2 DVD I'm trying to play in Region 1 land. It was the VDPAU playback profile. In fact I found the ticket with a link to Stephen's clip, apparently added by Jean-Yves:
> https://code.mythtv.org/trac/ticket/11377
> http://www.avenard.org/files/media/mediatest/Ondine_clip.mpg
> the
> I downloaded that clip and I get exactly the same distorted black blocks I see with my DVD. And the clip and the vob extracted from my DVD both play fine for me with "mplayer -vo vdpau -vc ffmpeg12vdpau ..." And if I change to a non-VDPAU profile, MythTV can play the DVD, the vob and the Ondine clip just fine. So I'm 99.9% sure my problem is the same as the described in the ticket.
>
> We have been using MythTV as a region free DVD player for years, using it to play content we can't get in NTSC/region 1 format but can get from amazon.co.uk. We didn't think we'd have any problem with our latest purchase, a DVD box set of Dalziel and Pascoe that has English audio and Dutch subtitles. Maybe they did something odd when they added the Dutch subtitles? At any rate, many (but not all) of the DVDs are unwatchable with a VDPAU profile.
>
> Anyway, since I've got an investment in DVDs that I can't play unless I switch back and forth between playback profiles, I thought I'd see if I could find a real solution to the problem. I see at least two lines of inquiry to pursue:
>
> 1) Try out different NVidia drivers. I've got 304.116. The original ticket author had 304.43. Maybe the latest recommended driver fixes the problem. But how likely is a new driver to fix the problem? Given the fact that the content in question plays with mplayer using both VDPAU rendering and decoding, doesn't that suggest the root cause is more likely in MythTV code than in VDPAU driver code?
>
> 2) First confirm that it's VDPAU decoding and not rendering that's the problem, as suggested by peper03 in this thread:
> http://www.gossamer-threads.com/lists/mythtv/users/538080
> Then, figure out how MythTV and mplayer/ffmpeg12vdpau code differ when it comes to using VDPAU decoding. It mean wading into code I've never looked at before. But I used to be pretty good at reading, understanding and fixing other people's code, and I have developed a basic understanding of the MPEG-2 protocol over the years (written a little program that can parse program stream headers), so maybe its within my abilities?
>
> Since I think the topic is now veering in to development territory, I'm CCing that group.
>
> I welcome feedback and any other ideas,

Hi Helen,

Sorry for not seeing this thread earlier.  I've been up to my ears in 
work recently.

I don't have an awful lot to add but it's definitely not a DVD problem.

I submitted a test file to NVidia and, as I wrote in the ticket, they 
confirmed they could reproduce it with MythTV but not with mplayer.  I 
don't know whether that means that MythTV is doing something wrong that 
mplayer is doing right, or maybe MythTV is using some feature of VDPAU 
that mplayer isn't.  I don't really know anything about the video 
decoding process.

I've just sent another email to NVidia to ask if they have any further 
information.  I'm not holding my breath but since they should have a 
fair bit of expertise in this area, I'm hoping they may be able to give 
some pointers (e.g. the affected videos happen to use some special 
feature of MPEG2 that most other don't).

If I get a reply, I'll report back here.

Regards,

Richard.