Closing GOP Structures

[yamyam]

Can someone tell me what the CLOSE ALL GOPS option actually does in CCE, do i need to tick this or not ?, what does it mean if i leave the GOPS open ?

What does equalize each gops bit length do ?

what is add sequence end code ?

Thanks, im pretty new to CCE SP, just getting used to the settings, only ever used TMPG before.

[RB]

RTFM!

[snowbeach]

I RTFM regarding the question: What is Add sequence end code?
The result from the CCE Manual...

3.6.2 Adding sequence end code

It is possible to specify whether the sequence end code should be
added at the end of an encoded video stream or not. To add the
sequence end code, select Add sequence end code check box.

Ha, ha, ha, ha... Not very helpful! Isn't it?! :D

[yamyam]

The CCE manual is not very helpful, like you just said, i turned to the forums to find out what these things actually mean but as you can see i didnt get a very helpful reply.

Maybe someone, someday could provide helpful answers.
Instead of just saying: RTFM

[digitalman]

Closing the GOP's makes editing easier in an MPEG video editing suite. There will be less seek time moving through the MPEG. Closing the GOP's or equalizing the length causes your video to grow in size considerably, so if you are not editing or want to keep the file size down, do not close the GOP's. I have not had any issues enabling or disabling the end code. Maybe some software editing or DVD creating packages need this end code in the mpeg file.

[kheops]

hi,

in the registered version of BitrateViewer you can see gops details of a given vob file

here is what i have for ocean 11


Gop no.,Timecode,Pic n.,Pictures,Closed,Broken l.,Has SeqHdr,Offset
1,00:59:58.22,15,IBBPBBPBBPBBPBB,Yes,No,Yes,0000098
2,00:59:59.12,15,IBBPBBPBBPBBPBB,No,No,Yes,0003ef4
3,01:00:00.02,15,IBBPBBPBBPBBPBB,No,No,Yes,0007d4c
4,01:00:00.17,15,IBBPBBPBBPBBPBB,No,No,Yes,000be80
5,01:00:01.07,15,IBBPBBPBBPBBPBB,No,No,Yes,0061af8
6,01:00:01.22,15,IBBPBBPBBPBBPBB,No,No,Yes,00df04c
7,01:00:02.12,15,IBBPBBPBBPBBPBB,No,No,Yes,0168968
8,01:00:03.02,15,IBBPBBPBBPBBPBB,No,No,Yes,01f332c
9,01:00:03.17,15,IBBPBBPBBPBBPBB,No,No,Yes,02948f8
10,01:00:04.07,15,IBBPBBPBBPBBPBB,No,No,Yes,031ddb4
11,01:00:04.22,15,IBBPBBPBBPBBPBB,No,No,Yes,03a3098
12,01:00:05.12,15,IBBPBBPBBPBBPBB,No,No,Yes,0423c8c
13,01:00:06.02,15,IBBPBBPBBPBBPBB,No,No,Yes,0495c88
14,01:00:06.17,15,IBBPBBPBBPBBPBB,No,No,Yes,04f9a14
15,01:00:07.07,15,IBBPBBPBBPBBPBB,No,No,Yes,055b4f8
16,01:00:07.22,15,IBBPBBPBBPBBPBB,No,No,Yes,05b9518
17,01:00:08.12,15,IBBPBBPBBPBBPBB,No,No,Yes,0616ea0
18,01:00:09.02,15,IBBPBBPBBPBBPBB,No,No,Yes,06708a4
19,01:00:09.17,15,IBBPBBPBBPBBPBB,No,No,Yes,06d24e0
20,01:00:10.07,15,IBBPBBPBBPBBPBB,No,No,Yes,0730db4
21,01:00:10.22,15,IBBPBBPBBPBBPBB,No,No,Yes,078cb5c
22,01:00:11.12,15,IBBPBBPBBPBBPBB,No,No,Yes,07e82a8
23,01:00:12.02,15,IBBPBBPBBPBBPBB,No,No,Yes,08431e8
24,01:00:12.17,15,IBBPBBPBBPBBPBB,No,No,Yes,089d0e0
25,01:00:13.07,15,IBBPBBPBBPBBPBB,No,No,Yes,08f8d80
26,01:00:13.22,15,IBBPBBPBBPBBPBB,No,No,Yes,0949510
27,01:00:14.12,15,IBBPBBPBBPBBPBB,No,No,Yes,097d6f8
28,01:00:15.02,15,IBBPBBPBBPBBPBB,No,No,Yes,09b7d9c
29,01:00:15.17,15,IBBPBBPBBPBBPBB,No,No,Yes,0a0b1e0
30,01:00:16.07,15,IBBPBBPBBPBBPBB,No,No,Yes,0a63d24
31,01:00:16.22,15,IBBPBBPBBPBBPBB,No,No,Yes,0abd9ac
32,01:00:17.12,15,IBBPBBPBBPBBPBB,No,No,Yes,0b17fe0
33,01:00:18.02,15,IBBPBBPBBPBBPBB,No,No,Yes,0b70568
34,01:00:18.17,15,IBBPBBPBBPBBPBB,No,No,Yes,0bd3ac8
35,01:00:19.07,15,IBBPBBPBBPBBPBB,No,No,Yes,0c3c4c4
191,01:01:52.22,15,IBBPBBPBBPBBPBB,No,No,Yes,4517e18
192,01:01:53.12,15,IBBPBBPBBPBBPBB,No,No,Yes,4574bf4
193,01:01:54.02,15,IBBPBBPBBPBBPBB,No,No,Yes,45d27a4
194,01:01:54.17,15,IBBPBBPBBPBBPBB,No,No,Yes,4633048
195,01:01:55.07,15,IBBPBBPBBPBBPBB,No,No,Yes,46907a8
196,01:01:55.22,15,IBBPBBPBBPBBPBB,No,No,Yes,46ece00
197,01:01:56.12,15,IBBPBBPBBPBBPBB,No,No,Yes,474bab4
198,01:01:57.02,15,IBBPBBPBBPBBPBB,No,No,Yes,47a9938
199,01:01:57.17,15,IBBPBBPBBPBBPBB,No,No,Yes,481fe44
200,01:01:58.07,15,IBBPBBPBBPBBPBB,No,No,Yes,488fa20
201,01:01:58.22,15,IBBPBBPBBPBBPBB,No,No,Yes,490485c
202,01:01:59.12,15,IBBPBBPBBPBBPBB,No,No,Yes,4972b1c
203,01:02:00.02,1,I,Yes,No,Yes,49e5e00
204,01:02:00.03,13,IPBBPBBPBBPBB,Yes,No,Yes,49ed4c0
205,01:02:00.16,15,IBBPBBPBBPBBPBB,No,No,Yes,4a3892c
206,01:02:01.06,15,IBBPBBPBBPBBPBB,No,No,Yes,4a95444
207,01:02:01.21,15,IBBPBBPBBPBBPBB,No,No,Yes,4aeff98
208,01:02:02.11,15,IBBPBBPBBPBBPBB,No,No,Yes,4b53be0
209,01:02:03.01,15,IBBPBBPBBPBBPBB,No,No,Yes,4bd7f0c
210,01:02:03.16,15,IBBPBBPBBPBBPBB,No,No,Yes,4c39290
485,01:04:48.16,15,IBBPBBPBBPBBPBB,No,No,Yes,bf1e170
486,01:04:49.06,15,IBBPBBPBBPBBPBB,No,No,Yes,bf7931c
487,01:04:49.21,15,IBBPBBPBBPBBPBB,No,No,Yes,bfd6850
488,01:04:50.11,15,IBBPBBPBBPBBPBB,No,No,Yes,c0333c0
489,01:04:51.01,15,IBBPBBPBBPBBPBB,No,No,Yes,c091c68
490,01:04:51.16,15,IBBPBBPBBPBBPBB,No,No,Yes,c0f01c4
491,01:04:52.06,15,IBBPBBPBBPBBPBB,No,No,Yes,c14bb70
492,01:04:52.21,15,IBBPBBPBBPBBPBB,No,No,Yes,c1a77dc
493,01:04:53.11,15,IBBPBBPBBPBBPBB,No,No,Yes,c203560
494,01:04:54.01,15,IBBPBBPBBPBBPBB,No,No,Yes,c25eee4
495,01:04:54.16,15,IBBPBBPBBPBBPBB,No,No,Yes,c2ba49c
496,01:04:55.06,7,IBBPBBP,No,No,Yes,c3165b4
497,01:04:55.13,13,IPBBPBBPBBPBB,Yes,No,Yes,c341bb0
498,01:04:56.01,15,IBBPBBPBBPBBPBB,No,No,Yes,c38f848
499,01:04:56.16,15,IBBPBBPBBPBBPBB,No,No,Yes,c3eb36c
500,01:04:57.06,15,IBBPBBPBBPBBPBB,No,No,Yes,c4514e8
501,01:04:57.21,15,IBBPBBPBBPBBPBB,No,No,Yes,c4b6120
502,01:04:58.11,15,IBBPBBPBBPBBPBB,No,No,Yes,c50f55c
503,01:04:59.01,15,IBBPBBPBBPBBPBB,No,No,Yes,c56fc9c
504,01:04:59.16,15,IBBPBBPBBPBBPBB,No,No,Yes,c5c5b78
505,01:05:00.06,15,IBBPBBPBBPBBPBB,No,No,Yes,c61fdf4
506,01:05:00.21,15,IBBPBBPBBPBBPBB,No,No,Yes,c6791b0
507,01:05:01.11,15,IBBPBBPBBPBBPBB,No,No,Yes,c6d130c
508,01:05:02.01,15,IBBPBBPBBPBBPBB,No,No,Yes,c7329e4
509,01:05:02.16,15,IBBPBBPBBPBBPBB,No,No,Yes,c78ee20
1071,01:10:39.21,15,IBBPBBPBBPBBPBB,No,No,Yes,195e5ed8
1072,01:10:40.11,15,IBBPBBPBBPBBPBB,No,No,Yes,196409f4
1073,01:10:41.01,15,IBBPBBPBBPBBPBB,No,No,Yes,1969efec
1074,01:10:41.16,15,IBBPBBPBBPBBPBB,No,No,Yes,196f7bec
1075,01:10:42.06,15,IBBPBBPBBPBBPBB,No,No,Yes,197554c4
1076,01:10:42.21,15,IBBPBBPBBPBBPBB,No,No,Yes,197b22d8
1077,01:10:43.11,15,IBBPBBPBBPBBPBB,No,No,Yes,1980d0e8
1078,01:10:44.01,15,IBBPBBPBBPBBPBB,No,No,Yes,19865cd0
1079,01:10:44.16,15,IBBPBBPBBPBBPBB,No,No,Yes,198b9e40
1080,01:10:45.06,15,IBBPBBPBBPBBPBB,No,No,Yes,1990c958
1081,01:10:45.21,15,IBBPBBPBBPBBPBB,No,No,Yes,19968ddc
1082,01:10:46.11,15,IBBPBBPBBPBBPBB,No,No,Yes,199c4274
1083,01:10:47.01,1,I,Yes,No,Yes,19a2319c
1084,01:10:47.02,13,IPBBPBBPBBPBB,Yes,No,Yes,19a2cadc
1085,01:10:47.15,15,IBBPBBPBBPBBPBB,No,No,Yes,19a7e0fc


i removed most of the lines, just to let you see than in commercial dvd all the gops aren't closed (in fact, many are NOT)

digitalman would you say that for a given filesize, quality is better if all the gops aren't closed ? i don't know exactly what that mean but i think it's not a problem if Closing the GOP's makes editing easier in an MPEG video editing suite

+

[adam]

Those closed GOPs are probably chapter points, and are only closed in order to have fast seeking to it. Most GOPs will remain open and there is no reason to arbitrarily close all GOPs unless you need to do extensive post encoding editing or if you need fast seeking, ie: multi-angle.

Given a decent bitrate you probably won't notice a difference between open and closed GOPs, but theoretically open is much more efficient and thus can potentially yield higher quality.

When you close a GOP it means it cannot reference the previous GOP. If there is any redundant information from that previous GOP which also appears in the following GOP, which basically happens everytime, than it must be stored a second time in the new GOP. You are basically storing the same information twice. Like I said, its inefficient but its not necessarily something you are going to notice.

If you are using a decent encoder there is no reason to close GOPs for most encoding jobs. If you use TMPGenc (IMO not a good encoder) than you may be forced to close GOPs. From my experience, the encoder does not even come close to maintaining your set GOP length unless you close the GOPs.