[MPlayer-users] Erroneous Aspect Ratio detection on DVDs with Pan&Scan Feature

[Alexander Roalter]

Nico Sabbi wrote:
> Alexander Roalter wrote:
> 
>> Hello,
>> another issue which I came across and has never been addressed on this 
>> list will be presented in this posting:
>>
>> It's about DVDs which have a Pan&Scan flag. Such a flag should in 
>> theory tell the player how to zoom into a video (given the case the 
>> DVD player is set to P&S instead of 4:3LB or 16:9), which should also 
>> include the possibility to PAN around (not simple zoom), but in all 
>> cases I've encountered so far does only zoom in (as with pressing the 
>> 'e'-Key in mplayer until the picture is full frame).
>>
>> I've had this with older James Bond DVDs and recently on my Raging 
>> Bull Ultimate Gold Edition (German Version). This should be 
>> practically identical to the british Raging Bull Cinema Reserve or MGM 
>> Ultimate Edition.
>>
>> Problem is: Although these DVDs are encoded anamorphic, mplayer thinks 
>> they're not and shows a stretched picture. Adding -aspect 16:9 helps, 
>> but this should be done automatically, as the correct aspect ratio is 
>> misdetected.
> 
> 
> I agree, IMO lavc treats incorrectly this kind information.
> I guess it should leave DAR and SAR unchanged and export in AVPanScan 
> the WxY set in the
> sequence_extension.
ok, now from what I found out (together with the info I gathered this 
afternoon, there could be a way to find out if this pan&Scan is active 
and therefore either a) the aspect ratio has to be overridden 
(automatically) with 16:9 or b) the aspect ratio has to be overridden 
and the picture zoomed into (-panscan 1), as it would be on a TV-Set 
with "4:3 P&S"-Setting. Default behavior should be 4:3 LB or 16:9 LB 
(doesn't make really a difference on a computer, and with -monitoraspect 
one can emulate anamorphic output on the TV-Out to gain vertical resolution.


Now, in the libdvdread (not the one in mplayer, but the real separate 
lib, version 0.9.6) contains some programs in its src-Directory. first 
comes ifo_dump.

When applied to my Raging-Bull-DVD, I get (amongst other things) the 
following lines:


Start sector of VTS_C_ADT:       0000000d
Start sector of VTS_VOBU_ADMAP:  0000000e
Video attributes of VTSM_VOBS: mpeg2 pal 16:9 only pan&scan U0 Variable 
Bit Rate 720x576 video
VTSM Number of Audio attributes: 1
         stream 1 status: ac3 48kHz 2Ch Not specified 0
VTSM Number of Sub-picture attributes: 1
         stream  1 status: -- Unspecified --
Video attributes of VTS_VOBS: mpeg2 pal 16:9 pan&scan+letterboxed U0 
Variable Bit Rate 720x576 video
VTS Number of Audio attributes: 7
         stream 0 status: ac3 en ( ) 48kHz 6Ch Not specified 0
         stream 1 status: dts en ( ) 48kHz 6Ch Not specified 0


While all other anamorphic DVDs (without this pan&scan thingo show

Start sector of VTS_VOBU_ADMAP:  00000027
Video attributes of VTSM_VOBS: mpeg2 pal 16:9 only letterboxed U0 
Variable Bit Rate 720x576 video
VTSM Number of Audio attributes: 1
         stream 1 status: ac3 48kHz 2Ch Not specified 0
VTSM Number of Sub-picture attributes: 1
         stream  1 status: -- Unspecified --
Video attributes of VTS_VOBS: mpeg2 pal 16:9 only letterboxed U0 
Variable Bit Rate 720x576 video
VTS Number of Audio attributes: 8
         stream 0 status: ac3 en ( ) 48kHz 2Ch Not specified 0
         stream 1 status: ac3 de ( ) 48kHz 2Ch Not specified 0


its also a matter of finding out if there's this "pan&scan+letterboxed" 
or "only letterboxed"

I'm still at a loss finding out which of these lines is the right one. 
it's the VTSM_VOBS or VTS_VOBS-Line???

any help?