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

Fri Apr 4 06:13:14 UTC 2014

2014-04-03 21:13 GMT+02:00 Richard Hulme <peper03 at yahoo.com>:
> 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).

FWIW, I have multiple DVB-C MPEG2 channels which are unwatchable due
to pixelation when using the MythTV VDPAU decoder. It plays fine when
using another decoder or using mplayer with VDPAU. I don't know if
you're seeing the same thing, but if I playback an affected recording
with a non-VDPAU decoder profile, seeking will be inaccurate even
though playback is fine.

Best regards
Kenni