VC-1 decoding errors

When you can DL please have a look at the clip I linked

Unfortunately I can’t do much downloading. If you can tell me a movie (and give me a rough timestamp) where you see it I can check; assuming that I have that movie.

The blocking is one of the issues but not the only one. The closest comparison I would make is that everything looks like it has been badly transcoded to a low bitrate , resulting in lots of obvious banding and posterisation in gradients, a smeary look to film grain as a result DNR and just a general loss of any high frequency detail.

My assumption is that there is some sort of processing filter being applied only to VC-1 when being decoded by hardware, as it doesn’t affect any other codec from what I can tell.

Couple of quick examples if you have them (all blu-ray rips so untouched video)

Blood Diamond - 20 secs in there are some light shafts that make up one of the logos. Lots of posterisation and banding can be seen.

Body of lies - 00:12:42 - Close up on the face you can see lots of smearing and loss of detail. Tell tale “waxy” look from DNR

Sherlock Holmes (2009) This one is really bad, all the film grain is mushy, banding in colours etc…

Pretty much any shot from the Planet Earth blu-ray ( the first series) looks terrible.

To me it is obvious with all VC-1 files, not just specific clips. Comparing playback with something else ( or disable hardware decoding) should show the difference immediately.

Unfortunately, I don’t happen to have any of those movies/TV Shows. Figures…

To make it easier to find a movie that we both have, here’s a list of my VC-1 Movies. Hopefully you have one of them.

"A Christmas Story"
"A Nightmare on Elm Street"
"American Pie 2"
"An American Werewolf in London"
"Animal House"
"Austin Powers in Goldmember"
"Austin Powers: International Man of Mystery"
"Austin Powers: The Spy Who Shagged Me"
"Battlestar Galactica"
"Doctor Zhivago"
"Fast Times at Ridgemont High"
"Forbidden Planet"
"Gone with the Wind"
"Grumpier Old Men"
"Grumpy Old Men"
"Harry Potter and the Chamber of Secrets"
"Harry Potter and the Goblet of Fire"
"Harry Potter and the Half-Blood Prince"
"Harry Potter and the Order of the Phoenix"
"Harry Potter and the Philosopher's Stone"
"Harry Potter and the Prisoner of Azkaban"
"Love Actually"
"Mamma Mia!"
"National Lampoon's European Vacation"
"Purple Rain"
"Sixteen Candles"
"Taking Lives"
"The Mask"
"The Polar Express"
"The Shining"
"The Switch"
"Weird Science"

I have a number of those as well, however I had completley forgotten that you can take screenshots in Kodi, so its easy to make a comparison showing the issue.

I have uploaded a couple of quick comparison screenshots here that show the issue with the foced DNR on the Vero 4K when compared to the same MKV VC1 file played back in VLC (on my PC). You can clearly see that high frequncy detail is being lost on the Vero.

Caps taken from the same sample file mentioned before (clip of the file Constantine) along wiht a couple from the film Se7en.

Unique ID                                : 247069771915629624081559552862298751544 (0xB9DFE83ED15B58A78D09B7B24002C238)
Complete name                            : Z:\Codec Samples\VC1\VC-1_23.976_sample.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 105 MiB
Duration                                 : 59 s 978 ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 14.7 Mb/s
Encoded date                             : UTC 2015-05-28 12:23:49
Writing application                      : mkvmerge v7.9.0 ('Birds') 64bit
Writing library                          : libebml v1.3.1 + libmatroska v1.4.2

ID                                       : 1
Format                                   : VC-1
Format profile                           : Advanced@L3
Codec ID                                 : V_MS/VFW/FOURCC / WVC1
Codec ID/Hint                            : Microsoft
Duration                                 : 59 s 977 ms
Bit rate                                 : 13.4 Mb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.269
Stream size                              : 95.5 MiB (91%)
Language                                 : English
Default                                  : Yes
Forced                                   : No

ID                                       : 2
Format                                   : MLP FBA
Format/Info                              : Meridian Lossless Packing FBA
Commercial name                          : Dolby TrueHD
Codec ID                                 : A_TRUEHD
Duration                                 : 59 s 977 ms
Bit rate mode                            : Variable
Bit rate                                 : 1 356 kb/s
Maximum bit rate                         : 3 267 kb/s
Channel(s)                               : 6 channels
Channel layout                           : L R C LFE Ls Rs
Sampling rate                            : 48.0 kHz
Frame rate                               : 1 200.000 FPS (40 SPF)
Bit depth                                : 24 bits
Compression mode                         : Lossless
Delay relative to video                  : 1 ms
Stream size                              : 9.70 MiB (9%)
Title                                    : 5.1
Language                                 : English
Default                                  : Yes
Forced                                   : No

00:00:00.000                             : en:Chapter 19
00:00:07.007                             : en:Chapter 20

Thanx a lot for the screenshots but only the VLC seem to show.
Edit: Works on Chrome

We have some VC-1 improvements coming in our next kernel. I suspect that this will resolve things and we have had @bmillham do some extensive testing.

Sounds interesting! Do we have any idea at all when that might be available? Weeks? Months?

When it’s ready :slight_smile:

Just a note, for housekeeping purposes, that the VC-1 decoding errors I was complaining about in posts 1 and 6 of this thread have been fixed in the September 2022 software release.

VC-1 playback on RPi 4B is not fixed in the September release (but that wasn’t to be expected as the RPi 4 does not have any VC-1 hardware acceleration).

Well, yes. But this is a thread about VC-1 playback on the Vero 4K(+).

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