DVD video color disappearing when playing VOB's, not when playing DVD

[lelegard]

Hi,

I run into an unusual phenomenon with one commercial DVD. The movie is "The Rocky Horror Picture Show" from the 20th Century Fox, 1975.

The colors of the video are correct when I play the movie from the DVD menu using either a home player or VLC on Windows 10. However, when I play directly one VOB from VLC or when I convert the video to any format using ffmpeg, the colors continuously disappear to black and white, and then re-appear, then disappear, etc.

I have been working for years with DVD's, converting them for my iPad, creating DVD's from my TV recordings, etc. I also developed QtlMovie, a specialized GUI front-end for ffmpeg to automate this. So, I have seen hundredths of DVD's but it is the first time I see this.

Let me be more specific. When I play the DVD on a home player, everything is fine. When I play the DVD as a disc (using dvd:///H: as parameter for VLC), everything is fine either, the colors of the video are normal and stable. However, when I directly open any VOB file with VLC, the colors come and go, alternating with black and white. If I convert one single VOB or the complete movie to divx or H.264 using ffmpeg and play the resulting file with VLC, I get the same behavior with colors alternating with black and white.

I have never seen that before.

I suspect some timestamping issue. While converting with ffmpeg, I see many errors like this

Error while decoding stream #0:2: Invalid data found when processing input
[aac @ 0000000000deaa20] Queue input is backward in time
[mp4 @ 0000000004b6b020] Non-monotonous DTS in output stream 0:1; previous: 12280960, current: 12280448; changing to 12280961. This may result in incorrect timestamps in the output file.

Regenerating output time stamps using "-fflags +genpts" does not change anything to the color issue.

I also see many messages like this:

[dvd @ 000000000126b580] buffer underflow st=0 bufi=1154 size=1536
[dvd @ 000000000126b580] buffer underflow st=0 bufi=584 size=1536
[dvd @ 000000000126b580] buffer underflow st=0 bufi=1067 size=1536
[dvd @ 000000000126b580] buffer underflow st=0 bufi=980 size=1536

Increasing the buffer size using "-bufsize 5000k" or any arbitrary large value does not change anything.

That being said, I do not worry too much since I am used to see thousands of similar warning messages from ffmpeg without significant impact on the result.

The fact which really puzzles me is that the same VLC player on the same DVD media displays correct colors when playing the movie from the DVD menu and unstable colors when playing the VOB file.

Does anybody have an explanation on this?

How can I convert the movie with stable colors? After all, my real goal is to watch the file on my iPad and convert it to a .mp4 file.

You will find below the output of MediaInfo on the first VOB file, if it helps.

Thanks
-Thierry

General
Complete name                            : H:\VIDEO_TS\VTS_01_1.VOB
Format                                   : MPEG-PS
File size                                : 1 024 MiB
Duration                                 : 14mn 11s
Overall bit rate mode                    : Variable
Overall bit rate                         : 10.1 Mbps

Video
ID                                       : 224 (0xE0)
Format                                   : MPEG Video
Format version                           : Version 2
Format profile                           : Main@Main
Format settings, BVOP                    : Yes
Format settings, Matrix                  : Custom
Format settings, GOP                     : M=3, N=15
Duration                                 : 14mn 11s
Bit rate mode                            : Variable
Bit rate                                 : 9 315 Kbps
Maximum bit rate                         : 6 800 Kbps
Width                                    : 720 pixels
Height                                   : 576 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 fps
Standard                                 : PAL
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Scan order                               : Top Field First
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.898
Time code of first frame                 : 00:59:58:10
Time code source                         : Group of pictures header
Stream size                              : 945 MiB (92%)

Audio #1
ID                                       : 189 (0xBD)-128 (0x80)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Muxing mode                              : DVD-Video
Duration                                 : 14mn 11s
Bit rate mode                            : Constant
Bit rate                                 : 384 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Frame rate                               : 31.250 fps (1536 spf)
Compression mode                         : Lossy
Delay relative to video                  : -32ms
Stream size                              : 39.0 MiB (4%)

Audio #2
ID                                       : 189 (0xBD)-129 (0x81)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Format profile                           : Dolby Digital
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Muxing mode                              : DVD-Video
Duration                                 : 14mn 11s
Bit rate mode                            : Constant
Bit rate                                 : 96.0 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 48.0 KHz
Frame rate                               : 31.250 fps (1536 spf)
Compression mode                         : Lossy
Delay relative to video                  : -16ms
Stream size                              : 9.74 MiB (1%)

Audio #3
ID                                       : 189 (0xBD)-130 (0x82)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Format profile                           : Dolby Digital
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Muxing mode                              : DVD-Video
Duration                                 : 14mn 11s
Bit rate mode                            : Constant
Bit rate                                 : 96.0 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 48.0 KHz
Frame rate                               : 31.250 fps (1536 spf)
Compression mode                         : Lossy
Delay relative to video                  : -16ms
Stream size                              : 9.74 MiB (1%)

Text #1
ID                                       : 189 (0xBD)-36 (0x24)
Format                                   : RLE
Format/Info                              : Run-length encoding
Muxing mode                              : DVD-Video

Text #2
ID                                       : 189 (0xBD)-37 (0x25)
Format                                   : RLE
Format/Info                              : Run-length encoding
Muxing mode                              : DVD-Video

Text #3
ID                                       : 189 (0xBD)-38 (0x26)
Format                                   : RLE
Format/Info                              : Run-length encoding
Muxing mode                              : DVD-Video
Duration                                 : 14mn 10s

Text #4
ID                                       : 189 (0xBD)-32 (0x20)
Format                                   : RLE
Format/Info                              : Run-length encoding
Muxing mode                              : DVD-Video

Text #5
ID                                       : 189 (0xBD)-33 (0x21)
Format                                   : RLE
Format/Info                              : Run-length encoding
Muxing mode                              : DVD-Video

Text #6
ID                                       : 189 (0xBD)-34 (0x22)
Format                                   : RLE
Format/Info                              : Run-length encoding
Muxing mode                              : DVD-Video

Menu

[jagabo]

VOB files may not be linear. Often two different versions of the video are interleaved, a few seconds of one, a few seconds of the other, etc. For example, I have a cartoon where the fully painted cells and the earlier pencil drawings are interleaved every few seconds. The IFO files determine which of the two video you see. In cases like this you need to use a program that de-interleaves the two videos. Like VOB2MPG.

[theewizard]

Why are you worried about playing the Vob files, they are Not stand alone files
Convert the whole disc to one movie, using main movie from Dfab or DVD shrink

[LigH.de]

A "DVD Video" is not just simply a sequence of files. It is a logical media structure. The content may be spread across several VOB segments. Their relations are described in the IFO files. Any program which does not care about the content of the IFO files and does not know how to process them is not recommendable to handle the content of a DVD Video media.

The colors of subpictures (in menus as well as in subtitles) in one example of information a program can't handle reliably when it does not care about IFO files.

To create a reliable copy of the main movie with subtitles, you can extract the "main movie PGC" from the DVD (with a ripper where stream processing is enabled, or with PGCDemux when you already ripped everything to the harddisk) in a way that the video stream and desired subtitle streams get written in a "PGC VOB" without splitting, and audio streams get written into separate audio stream files with possible sync delays in their file names; then you may process the PGC VOB together with a minimalistic IFO with VSRip to extract VobSub subtitles which should most probably have the correct color index values in the IDX file (but that can be checked additionally, e.g. with SubResync from a slightly older version of the VobSub tools by Gabest).

Keeping a copy as new authored movie-only DVD using DVD Shrink may of course be the easiest solution.

[lelegard]

Thanks for the idea. Do you mean two angles? In that case, are the different angles in the same video stream? VLC and MediaInfo detect only one video stream.

I wanted to try VOB2MPG anyway but it crashes on Windows 10. It seems to be an old unmaintained program. Too bad. Any other idea to

[LigH.de]

"Multi-angle" means that there is mostly one video stream, but there may be a second (or more) video stream in parallel to usually rather short scenes only. Therefore a header analyzing tool like MediaInfo may not be able to detect their presence when their appearance is rather late in a VOB file. But their presence will be detectable for programs which know how to handle IFO files (e.g. DVD rippers or PGCDemux, as well as content reducers like DVD Shrink).

[lelegard]

OK, thanks. My understanding of the PGC was incorrect. The VOB's contains 3 PGC's. PGC Demux did the trick. The colors are stable when only the first PGC is extracted.
Thanks again