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Old 19th November 2017, 00:33   #1  |  Link
Shandra
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Join Date: Mar 2003
Posts: 90
Merging Encodes of a Movie spawned over multiple DVDs (LotR SEE)

Ok, I am really not sure into which subforum this question should be placed, so I've selected the Newbies...

[Context]
* DVDs for Lord of the Rings Special Extented, each Movie is spawned over 2 DVDs (Ok, the following could possible be applied to true 2 sided DVDs of old or other similar cases)
* I wanted to merge the encodes of each movie into one file using mkvtoolnix-gui (video->x264, audio: keeping AC3 for Multichannel, AAC (QAAC) for 2.0, Subtitles (forced) [converted from vobsubs to srt with subtitle edit] + chapter indices).
* SRT Subtitles because I wanted to remove the black (Top/Bottom) Borders for the encoded videoframe and to have the possibility that a player could render the subs below the videoframe.

[Observation]
* Encoding both parts with the same setting for x264 and the same parameters within the avs script with MeGUI for uncroped Frame and Frame croped by 72/72 Top/Bottom (having in mind a Mod16 for the Result) resulted in (1st muxed each part in mkvtoolnix-gui/mkvmerge, then appending 2nd mkv to 1st mkv): Encode of full Frame (720x576) merged fine, croped encode delievers mostly grey macroblocks/garbage for the merged 2nd part of the video whence decoding.
* merging with Avidemux (Only the Videostreams and it would be nice if that one would honour PAR/DAR besides PAR 1:1) produced the same garbage for the 2nd part of the merged result.
* In another Encode -> Cropping 64/64 Top/Bottom went fine for the merge (as it was for the uncroped Encode)

[Question]
As Each Encode of Both Parts played Fine on its own, regardless wether Macroblocks of the Source where honoured or not (As we are all used to with encodes, regardless if we crop to MOD16 or just MOD2 and that cutting 8 Top+8 Bottom still resulted in MOD16 for the encoder); I don't get it why 2 Videostreams that where encoded with the same settings, but cropped the m2v (Edit: Ok, using d2v, but the source still is m2v within vob) source within macroblocks, can't be merged to be decoded properly, but if both encodes where croped honouring the macroblocks of the source could...

I really have no Idea wether this is a MeGUI, x264, mkvtoolnix or whatsoever problem - And as the 64&64 Crop is working I don't wan't any suggestions in regards of the encodes, but I am really puzzled why in this case of merging the encodes, it is needed to honour the 16x16 macroblock size of the source for both encodes.

[Edit:
P.S.: My 1st Encodes in this case are over a month old (was within an update-cycle of mkvtoolnix, the olderup2date version doesn't wanted to merge those croped files, the updated one accepted 'em) , and encountering the problem I tried multiple searches (here within the Forum and on the Web in general), but for the decoding problem of the merge I only found a few cases mentioning it, but not a real solution... The Idea of the multiples of 16 crop top/bottom just came within a private discussion 2 days ago, and as I am really/really and really not getting it why this is working, i've decided to post the "question"/proclaim the "observation" here - so please, don't ask for some logs or such for the described observations, all I can deliver is the mediainfo for the encodes of both parts I still have for some of the various encodes.]

Last edited by Shandra; 19th November 2017 at 01:14.
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