suggestion for divx

[gsharad007]

as most movies have letterboxing y doesnt divx support letterboxing. in this one can specify the letterboxing and then encoder can remove those parts and when run the decoder can re add those parts and now we get better quality/ smaller sizes.

dont suggest to me to crop those parts as i encode the movies at their original resolution and if some movies are 16:9 they are compressed to the correct aspect ratio and i get sharper better quality.

[Sharktooth]

:readguid:
Cropping black bars and resizing to the correct aspect ratio...

or

Cropping black bars and set the correct aspect ratio...

[gsharad007]

Originally posted by Sharktooth
:readguid:
Cropping black bars and resizing to the correct aspect ratio...

or

Cropping black bars and set the correct aspect ratio...

i asked ppl specially not to reccomend that

[jggimi]

What you are asking for is not letterboxing, but anamorphic Pixel Aspect Ratios (PARs), since there are no fixed resolutions.

You are free to use anamorphic encoding with DivX, as long as you play back with players that support aspect ratio adjustment by the user, such as BSPlayer.

There are other MPEG-4 codecs that support anamorphic PARs, such as XviD. You are welcome to experiment with them.

Regarding letterboxing:

DVDs have anamorphic Display Aspect Ratios (DARs) with fixed resolutions. Because there are only two DARs -- 4:3 or 16:9 -- and many different video and film aspect ratios, DVDs will contain letterboxing or pillarboxing in the video streams.

[Sharktooth]

CROPPING is needed to remove the black bars and spare the bitrate...
RESIZING is needed to have the correct AR. In place of resizing you can do an ANAMORPHIC encode and set the correct AR value (xvid does it... but not all decoders support it) or use a player capable of resizing (BSPlayer, Media Player Classic ...).

[SeeMoreDigital]

Originally posted by Sharktooth
CROPPING is needed to remove the black bars and spare the bitrate...
RESIZING is needed to have the correct AR. In place of resizing you can do an ANAMORPHIC encode and set the correct AR value (xvid does it... but not all decoders support it) or use a player capable of resizing (BSPlayer, Media Player Classic ...).

As far as I know, both BS Player and MediaPlayer Classic will not auto AR "anamorphic" Mpeg4 encodes (with PAR signalling), unless you have the required direct-show decoder filter installed.

VideoLAN is one of the very few software players capable of auto AR "anamorphic" Mpeg4 encodes, without installing a filter.

And by-the-way, DivX can't generate anamorphic encodes!


Cheers

[jggimi]

DivX can't generate anamorphic encodes!That comment is misleading. But, if instead, you meant that there is no PAR flag available with DivX, that would be correct.

I wrote, above: You are free to use anamorphic encoding with DivX, as long as you play back with players that support aspect ratio adjustment by the user, such as BSPlayer.I stand by that statement. As an example BSPlayer will default to square pixels, like any AVI player. But it can also resize to 4:3 or 16:9 on command. This allows one to playback DivX encoded with non-square pixels. Because it is limited to those DARs, though, its use is effectively limited to unresized DVD content.

[Sirber]

You can set Matroska to output to conrrect AR or rez IIRC.

[SeeMoreDigital]

Hi jggimi,

In reality I think it's a great shame that generating and decoding Mpeg4 encodes with PAR (or DAR) signalling is not a standard function with all Mpeg4 codecs (just like we have with DVD), as it's continuing to confuse many people :confused:

Bizarrely the newest version of the DivX codec contains so called "anamorphic" settings: -

http://img60.exs.cx/img60/9114/SMD_DivX_encoder_settings.gif

In my opinion, this just adds to the confusion and should be removed


Cheers

[stephanV]

its not confusing, youre just misunderstanding it... :p

it refers to the *source* and indeed "anamorphic 16:9" is a normal way to indicate a 16:9 anamorphic source. notice there is also letterbox 16:9 and 4:3, which again refers to the source.

[SeeMoreDigital]

Originally posted by stephanV
its not confusing, youre just misunderstanding it... :p In my opinion they "are" and total waste of time!

They may also mislead some inexperienced users into believing that the resulting output encode is anamorphic

[stephanV]

not misleading... theres no other way of doing it...

if you want to use Home Theater Generic profile and have a 16:9 anamorphic DVD you need to know what option to choose right? I cant see any other way that would be less confusing.

[gsharad007]

Originally posted by stephanV
not misleading... theres no other way of doing it...

if you want to use Home Theater Generic profile and have a 16:9 anamorphic DVD you need to know what option to choose right? I cant see any other way that would be less confusing.

guys guys back to the topic pls.

wat i do is exact encoding of the video at the original pixel size widout aspect-ratios. since divx decoder as ration settings i use that. wat the problem is that for the decoder end ratios to work (more that 16.9 missing) i have to encode the movie at fullsize. but if i specify letterbox then those portions can be removed and later added in decoding and still make way for ratios.

[stephanV]

sharktooth and jggimi already answered your questions

if you set PAR, you don't have to let the decoder add a letterbox as any decoder that reads out the PAR will put out the right framesize automatically. (it also wouldnt be necessary anymore to set the AR in the decoder settings)

Instead of making a weird workaround which probably isnt MPEG4 compliant anyway, you're better of asking the DivX team for DAR/PAR signalling in the bit stream :)

[SeeMoreDigital]

Originally posted by stephanV
...Instead of making a weird workaround which probably isnt MPEG4 compliant anyway, you're better of asking the DivX team for DAR/PAR signalling in the bit stream :) On this point we agree...

Needless to say I've asked... many times

I've even received "private messages" from thekid (and others at DNX), asking questions like "what would you like to see added to DivX"... but still to no avail.

If the likes of Nero, XviD and 3ivx can add it to their decoders... why can't DivX?


Cheers

[iradic]

is this possible with mpeg4 modifier ... adding/changing aspect ratio for divx i mean...

[stephanV]

i havent tried it, but it should work i suppose. you still need a decoder that reads out the PAR signal though.

[SeeMoreDigital]

Originally posted by iradic
is this possible with mpeg4 modifier ... adding/changing aspect ratio for divx i mean... Of course it's possible!

That said, Mpeg4 Modifier does not like some types of "Open DML" AVI encodes, including Mpeg4 streams de-muxed by AVI-mux.


Cheers

[stephanV]

you can set both virtualdub and avimux to write avi 1.0, so as long your file is not >2GB it shouldnt be a problem i guess.

could you more specific about the problems with openDML in mpegModifier? does it have to do with legacy index or not?

[SeeMoreDigital]

Originally posted by stephanV
...could you more specific about the problems with openDML in mpegModifier? does it have to do with legacy index or not? For more information regarding Motiah's Mpeg4 Modifier tool, why not have a look at his web site: -

http://www.moitah.net/

For more info regarding Open DML, have a look here (http://www-user.tu-chemnitz.de/~noe/Video-Zeug/AVIMux%20GUI/en_about_opendml.html)

[stephanV]

yeah i know what openDML is :p

so it doesnt support openDML at all... thats... not very handy... ah well :)

[SeeMoreDigital]

Originally posted by stephanV
...so it doesnt support openDML at all... thats... not very handy... ah well :) Well, it all depends on the interpretation of OpenDML.

I use MPEG Mediator to generate most of my Mpeg4 encodes.. and according to it's creator and GSpot, it creates OpenDML streams!

Strange then, that MPEG4 Modifier can work with them :)


Cheers

[stephanV]

im just repeating from the site :)

ill try out though

BTW - how can you interpretate openDML? a file either is openDML or it isnt.

Alexnoe had a nice comment lately about GSpot and the detecting of openDML though... cant remember where the thread is.

[edit]it doesnt accept openDML from avimux GUI, which is currently the only app i trust in writing such avis. it would be pointless too to support it as MPEGmodifier cant write openDML yet anyway.