[XviD-devel] XviD 1.1.0-beta2 is out!

Michael Militzer michael at xvid.org
Mon Apr 4 14:50:02 CEST 2005


Hi Guillaume,

no, there is more to it than just this flag. First, there are several DivX
profiles, which support different features. So depending on which profile
the user chooses, a certain subset of features needs to be disabled. E.g. 
none of the DivX profiles support qpel. The DivX Handheld profile does not
support B-frames at all whereas within the DivX Home Theatre B-frames are
allowed but not more than one consecutive b-frame.

These restrictions are not enforced within xvidcore but it's the 
responsibility of the user frontend (VfW, MEncoder) to disable not supported
features if the DivX profiles are selectable in the frontend.

Apart from enforcing these restrictions, you'd also have to set the correct
vbv parameters for XviD's 2pass plugin depending on the respective DivX 
profile selected. Have a look at the vfw code for more details. Especially,
check the profiles table in config.c that lists the features supported by
the DivX profiles and the corresponding vbv parameters. Also see the file
codec.c, where the vbv parameters are set depending on the profile and
where other restrictions (e.g. the max b-frame limit) are enforced (search
for 'dxn').

bye,
Michael
 

Quoting Guillaume Poirier <poirierg at gmail.com>:

> Hi,
> 
> On Apr 4, 2005 1:17 PM, Michael Militzer <michael at xvid.org> wrote:
> >  - Improved compliancy with DivX profiles.
> 
> I'd be interested in adding the support for this feature to MEncoder,
> if possible.
> A quick glance at the latest xvid.h commit:
>  #define XVID_GLOBAL_VOL_AT_IVOP       (1<<3) /* write vol at every
> ivop: WIN32/divx compatibility */
>  #define XVID_GLOBAL_FORCE_VOL         (1<<4) /* when vol-based
> parameters are changed, insert an ivop NOT recommended */
>  #endif
> -
> +#define XVID_GLOBAL_DIVX5_USERDATA    (1<<5) /* write divx5 userdata string
> +                                                this is implied if
> XVID_GLOBAL_PACKED is set */
> 
> 
> ... tells me that DivX profile seems to be triggered just by setting
> the flag " XVID_GLOBAL_DIVX5_USERDATA".
> Am I right? Or is it triggered by another flag?
> 
> Regards,
> Guillaume
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> XviD-devel at xvid.org
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> 






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