Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion. Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules. |
8th December 2005, 01:12 | #281 | Link | |
Registered User
Join Date: Mar 2003
Posts: 87
|
Quote:
|
|
8th December 2005, 11:12 | #282 | Link | |
Life's clearer in 4K UHD
Join Date: Jun 2003
Location: Notts, UK
Posts: 12,219
|
Quote:
Cheers
__________________
| I've been testing hardware media playback devices and software A/V encoders and decoders since 2001 | My Network Layout & A/V Gear |
|
|
8th December 2005, 18:11 | #283 | Link |
Registered User
Join Date: Mar 2003
Posts: 87
|
Ah, yes indeed! I was using v1.3.0 which I got from one of the Doom9 guides. I got the YAMB 1.3.2 installer (containing MP4Box) from another forum thread now and it worked.
The from mp4 extracted avi has no artefacts! So what now? I can cut out a small part where artefacting occurs after unpacking with MPEG4Modifier and upload it so that someone can analyse the the cause maybe... Regards, eXistenZ_69 |
8th December 2005, 23:23 | #284 | Link | |
Registered User
Join Date: Feb 2004
Location: Virginia, USA
Posts: 334
|
Quote:
__________________
moitah.net |
|
8th December 2005, 23:27 | #285 | Link | |
Registered User
Join Date: Feb 2004
Location: Virginia, USA
Posts: 334
|
Quote:
__________________
moitah.net |
|
8th December 2005, 23:30 | #286 | Link | |
Life's clearer in 4K UHD
Join Date: Jun 2003
Location: Notts, UK
Posts: 12,219
|
Quote:
That said, are you 100% sure you did not fart about with the "User Data" settings in MPEG4 Modifier, prior to removing the packed bit-stream
__________________
| I've been testing hardware media playback devices and software A/V encoders and decoders since 2001 | My Network Layout & A/V Gear |
Last edited by SeeMoreDigital; 8th December 2005 at 23:34. |
|
9th December 2005, 08:49 | #287 | Link | |
Registered User
Join Date: Mar 2003
Posts: 87
|
Quote:
It's on 'auto' by default and I don't touch that. I just load the file, check unpack and save it... Greetz, eXistenZ_69 |
|
9th December 2005, 10:08 | #288 | Link |
Life's clearer in 4K UHD
Join Date: Jun 2003
Location: Notts, UK
Posts: 12,219
|
I'm sure any information will be useful to Moitah
__________________
| I've been testing hardware media playback devices and software A/V encoders and decoders since 2001 | My Network Layout & A/V Gear |
|
10th December 2005, 17:31 | #289 | Link |
Registered User
Join Date: Mar 2003
Posts: 87
|
I uploaded a file named 'problem_sample.rar' to a free online file hosting service (see link below). It contains a small fragment from the file that has the artefacting after unpacking with MPEG4Modifier. I included the unpacked versions by MPEG4Modifier and MP4Box as well. Size of the rar is 1.31MB.
http://www.freefileupload.net/file.p...lem_sample.rar I compared the info MPEG4Modifier shows for these three files and noticed the following: the unpacked version by MPEG4Modifier loses 1 P-VOP! The unpacked version by MP4Box still has all original VOP's. Another difference is that the MP4Box one has DivX999b000n, XviD0038 as user data, the MPEG4Modifier one only XviD0038 (auto setting was enabled during unpacking so this is as expected). I hope this enables Moitah to find and fix the bug! Regards, eXistenZ_69 |
10th December 2005, 21:00 | #290 | Link |
Registered User
Join Date: Feb 2004
Location: Virginia, USA
Posts: 334
|
Thanks for the sample files. I have found the problem. This video was encoded in segments and joined together. You can see this by using the "Write Frame List" button inside "Video Info", at frame 90 the timestamps jump backwards. The problem is that frame 89 is "packed" (it contains a P-VOP and a B-VOP), but there is no corresponding N-VOP placeholder to use for unpacking. In this case, I used to stop and show the error message "No dummy N-VOP found for packed frame", but in 1.3.0 I removed the error message and ignored the problem, without realizing more needs to be done.
I think I can fix this easily but I'm not sure yet, I don't have Visual Studio installed because I reinstalled Windows a few days ago. Hopefully I will have time tonight to do it.
__________________
moitah.net |
10th December 2005, 22:24 | #291 | Link |
Registered User
Join Date: Mar 2003
Posts: 87
|
Great you found the problem! I'm glad I could be of assistance. Should have mentioned that it concerns an encoding of a tv series...
I got a few questions regarding your explanation: 1) Is the fact that the timestamps jump backwards normal? 2) Does the problem occur on the join points of the segments? Strange, cause the point where artefacting occurs doesn't look like a moment where commercials where cut out (it's in the middle of a scene). 3) Is the artefacting because of a packed frame that didn't get unpacked or just left out? 4) Is it possible to detect affected unpacked files? 4) Is it possible to fix affected unpacked files? I don't have the original packed files of all files I've unpacked until now :-/ Take your time for the fix. No need to rush out a new version of MPEG4Modifier with a solution that hasn't been properly thought through Regards, eXistenZ_69 Last edited by eXistenZ_69; 10th December 2005 at 22:26. |
11th December 2005, 00:46 | #293 | Link | |||||
Registered User
Join Date: Feb 2004
Location: Virginia, USA
Posts: 334
|
Quote:
Quote:
Quote:
Quote:
Quote:
__________________
moitah.net |
|||||
11th December 2005, 03:50 | #294 | Link |
Registered User
Join Date: Feb 2004
Location: Virginia, USA
Posts: 334
|
I have fixed the problem. There's really no perfect way to handle this. If you make room for the extra VOP by shifting all the other VOPs forward (which I cannot do because of the way the code is currently structured), you will mess up the audio synch. The other way it to just remove the extra VOP, which is what I did. The latter is what would have happened anyway if the files were encoded with packed bitstream off before they were joined. Basically, the VOP sequence in this file isn't really valid because of the way it was cut. For anyone cutting/joining MPEG-4 ASP, I would recommend A) making all cuts on I-VOP boundaries (not only the beginning, but the end as well), and B) not using the frames after and including the last I-VOP, because XviD doesn't always end cleanly (it makes the last frame a B-VOP, which doesn't make any sense).
Also, I removed the "smart unpacking" code, which was supposed to handle files that contained real N-VOPs along with packed bitstream. I don't think any encoder does this, so it was just needlessly complicating the code. I don't know when I'll get around to releasing it, tomorrow if I have time.
__________________
moitah.net |
11th December 2005, 04:14 | #295 | Link | |
Registered User
Join Date: Jul 2004
Posts: 383
|
Quote:
|
|
11th December 2005, 12:48 | #296 | Link |
Registered User
Join Date: Nov 2001
Posts: 9,770
|
missing n-vops occur at the end of encodes, when the last frame is a packed one?
__________________
Between the weak and the strong one it is the freedom which oppresses and the law that liberates (Jean Jacques Rousseau) I know, that I know nothing (Socrates) MPEG-4 ASP FAQ | AVC/H.264 FAQ | AAC FAQ | MP4 FAQ | MP4Menu stores DVD Menus in MP4 (guide) Ogg Theora | Ogg Vorbis use WM9 today and get Micro$oft controlling the A/V market tomorrow for free |
11th December 2005, 14:07 | #297 | Link | ||
Registered User
Join Date: Mar 2003
Posts: 87
|
Quote:
Quote:
How does MP4Box handle this situation? How come playback of the packed bitstream doesn't show artefacting? Isn't the missing N-VOP needed there as well?? Regards, eXistenZ_69 Last edited by eXistenZ_69; 11th December 2005 at 14:19. |
||
11th December 2005, 14:17 | #298 | Link | |
Registered User
Join Date: Mar 2003
Posts: 87
|
Quote:
|
|
11th December 2005, 20:32 | #299 | Link |
Registered User
Join Date: Feb 2004
Location: Virginia, USA
Posts: 334
|
@bond: Yes, or it can add some B-VOPs afterwards. Ideally the end of the video should look something like:
Code:
(Frame#: VOPType) 57: P-VOP B-VOP 58: B-VOP 59: N-VOP Code:
58: P-VOP B-VOP 59: B-VOP Code:
59: P-VOP B-VOP
__________________
moitah.net |
11th December 2005, 21:07 | #300 | Link |
Registered User
Join Date: Feb 2004
Location: Virginia, USA
Posts: 334
|
eXistenZ_69: I think it's a lot easier to understand if you use the "Write Frame List" button and inspect the output.
Original packed video: Code:
89: P-VOP (0:00:03.840) B-VOP (0:00:03.756) 90: I-VOP (0:00:03.000) 91: P-VOP (0:00:03.125) B-VOP (0:00:03.041) 92: B-VOP (0:00:03.083) 93: N-VOP(D) (0:00:03.125) Code:
89: P-VOP (0:00:03.840) 90: B-VOP (0:00:03.756) 91: I-VOP (0:00:03.000) 92: B-VOP (0:00:03.041) 93: B-VOP (0:00:03.083) Unpacked in 1.3.3: Code:
89: P-VOP (0:00:03.840) 90: I-VOP (0:00:03.000) 91: P-VOP (0:00:03.125) 92: B-VOP (0:00:03.041) 93: B-VOP (0:00:03.083) Unpacked in MP4Box (frame numbers adjusted to compensate for MP4Box adding 2 delay frames near the beginning): Code:
89: P-VOP (0:00:03.840) 90: B-VOP (0:00:03.756) 91: I-VOP (0:00:03.000) 92: P-VOP (0:00:03.125) 93: B-VOP (0:00:03.041) 94: B-VOP (0:00:03.083)
__________________
moitah.net Last edited by Moitah; 11th December 2005 at 21:09. |
Thread Tools | Search this Thread |
Display Modes | |
|
|