How can I create a 2 sec solid black video clip without a video camera?

[haggis999]

I plan to create a compilation of clips extracted from a lossless MKV rip of one of my Blu-ray disks. Some sort of visible transition between these clips would be desirable but I don't want to re-encode the video. The only solution I can think of is to find or create a 2 second solid black video clip for use between each of my MKV extracts when I merge them using MKVMerge.

However, I don't have access to a video camera. Can anyone suggest how I might create such a divider clip? No audio track is required but I guess it would have to be 1920 x 1080 and 30fps, just like my Blu-ray extracts.

David

[poisondeathray]

I plan to create a compilation of clips extracted from a lossless MKV rip of one of my Blu-ray disks. Some sort of visible transition between these clips would be desirable but I don't want to re-encode the video. The only solution I can think of is to find or create a 2 second solid black video clip for use between each of my MKV extracts when I merge them using MKVMerge.

However, I don't have access to a video camera. Can anyone suggest how I might create such a divider clip? No audio track is required but I guess it would have to be 1920 x 1080 and 30fps, just like my Blu-ray extracts.

Unlikely to be 30fps . A blu-ray movie would be 23.976 or 24.0 fps

mkvmerge will only join similar spec clips, and you need audio to match, even if it's just silent audio. You should use mediainfo (view=>text) to determine . If something is off like the compression doesn't match, or framerate doesn't match, audio channels don't match, etc.. they won't join

You can create it with avisynth using blankclip() + x264 to encode if the video is h.264, or hcenc if thte video is mpeg2, or wmnicenc if the video is vc-1

[haggis999]

Thanks for the rapid and useful response.

I have just used MediaInfo to check the frame rate of several of the MKV files I have generated from my Blu-ray disks using MakeMKV and they were all 29.970 fps. Windows Explorer rounds this up to 30 fps.

The specific MKV file I wish to work on has its video described as follows by MediaInfo. Which tool would let me create a matching solid black clip?


Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Format settings, GOP : M=3, N=24
Codec ID : V_MPEG4/ISO/AVC
Duration : 1h 36mn
Bit rate mode : Variable
Maximum bit rate : 32.0 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : MBAFF
Language : English
Default : No
Forced : No
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

[poisondeathray]

Is there no audio?

Check the other videos first, that you want to have in the same compliation. They have to match specs or they won't append

If they are all like the one you posted, you can do this with avisynth + x264

I'll post farther instructions after you answer the other questions

[haggis999]

The audio tracks info is shown below, plus subtitle info in case that is also important for creating a suitable black divider clip.

Would there perhaps be a different solution to my problem that uses a modified version of a clip taken from the original MKV as the starting point for creating the divider clip? Obviously, such a clip would have all the matching video and audio settings but I would need an editing program that lets me reduce the audio volume to zero and dim the video to black.

Audio #1
ID : 2
Format : FLAC
Format/Info : Free Lossless Audio Codec
Codec ID : A_FLAC
Duration : 1h 36mn
Bit rate mode : Variable
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Title : 2/0
Writing library : MakeMKV v1.8.5 win(x64-release)
Language : English
Default : No
Forced : No

Audio #2
ID : 3
Format : FLAC
Format/Info : Free Lossless Audio Codec
Codec ID : A_FLAC
Duration : 1h 36mn
Bit rate mode : Variable
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Title : Lossless
Writing library : MakeMKV v1.8.5 win(x64-release)
Language : English
Default : Yes
Forced : No

Text #1
ID : 4
Format : VobSub
Muxing mode : zlib
Codec ID : S_VOBSUB
Codec ID/Info : The same subtitle format used on DVDs
Title : English - VOB
Language : English
Default : No
Forced : No

Text #2
ID : 5
Format : PGS
Muxing mode : zlib
Codec ID : S_HDMV/PGS
Codec ID/Info : The same subtitle format used on BDs/HD-DVDs
Title : English - PGS
Language : English
Default : No
Forced : No

[poisondeathray]

I think it's going to be tricky, unless everything matches, including the audio tracks. I don't know how subs will affect it

To do the video, you can make a script in avisynth

BlankClip(length=60, width=1920, height=1080, pixel_type="YV12")
AssumeFPS(30000,1001)
KillAudio()

You would use BD compliant settings that match your original "1080i29.97" - that's what the "MBAFF" is indicating

https://sites.google.com/site/x264bluray/home/1080i




You can generate 2 blank audio tracks (one stereo, one 5.1) with an audio editor (maybe audacity), and encode to flac

[poisondeathray]

Might be easier if I just did it quickly for you, but the process is outlined above

I used avisynth to do the audio as well using blankclip() and mergechannels() to make stereo and a 5.1 mix, soundout() to encode the flac , but you can just as easily use an audio editor

Here are the video, stereo, and 5.1 flac files

[haggis999]

Thanks once again for your kind assistance on this.

It's well after midnight here in the UK, so I'll play with your files in the morning. Just one quick question, though, before I head for bed - what tool do I use to combine your 3 files (blank.264, stereo.flac and 6ch.flac) into an MKV?

David

[shaema]

Here is a 2 seconds mkv file:

[poisondeathray]

what tool do I use to combine your 3 files (blank.264, stereo.flac and 6ch.flac) into an MKV?

mkvtoolnix - the same one you're going to be using for appending segments

[haggis999]

After hitting problems trying to append 2_sec.mkv (from shaema) to one of my Blu-ray extracts, I had a go at using poisondeathray's solution. This was more successful but I am still grappling with some MKVMerge issues. The blank black clip soundtrack was also not completely silent. When played via my hi-fi system there was a quiet buzzing sound.

I will report back later when I have had more time to investigate.

David

[poisondeathray]

Not sure why that would be.

If you play the audio in something like vlc, ffplay etc... it's completely silent

If you check the flac in an audio editor like audacity, it's completely silent and flatline

Perhaps something wrong with your setup ?

[shaema]

haggis999:

Could you attach a 10 or 15 seconds clip from your"Blu ray Extracts" so we can identify and fix the problem?

[poisondeathray]

There are several reason's why shaema's mkv probably didn't append properly:

AAC audio, missing audio track, progressive encoding (not MBAFF) , wrong timestamps, different level (4.0) , no HRD settings

[haggis999]

I've been out this evening but will work on this again tomorrow.

David

[haggis999]

I have uploaded two short samples taken from Chapters 2 and 5 of Britten's War Requiem. These should help in clarifying any issues in the creation of a suitable 2 second black clip for insertion between other extracts from that recording.

However, sorting out a divider clip for these specific samples does not necessarily help me to create a similar divider for samples taken from a different Blu-ray disk. That is why I proposed a different approach a couple of days ago, i.e. using a modified version of a clip taken from the original MKV as the starting point for creating the divider clip. Such a clip would automatically contain all the matching video and audio settings but I would need an editing program that lets me reduce the audio volume to zero and dim the video to black. Does such an editing program exist?

David

[smrpix]

Such a clip would automatically contain all the matching video and audio settings

Clever idea, but not necessarily correct, Blu Ray can contain different encoding in different sections. I have a disk, for example, where the main film is 1920x1080 24fps, but some of the bonus features are in 720x480 29.97.

I would need an editing program that lets me reduce the audio volume to zero and dim the video to black. Does such an editing program exist?

Any software that will do what you want will also create the black you need anyway. Check out TMPGenc Authoring Works.

[haggis999]

Thanks for the suggestion. I will have a look at TMPGenc Authoring Works. For my purposes, only the main feature will ever be relevant, so I assume that I will have no issues with different encoding settings.

David

[smrpix]

For my purposes, only the main feature will ever be relevant, so I assume that I will have no issues with different encoding settings.

That was meant as a specific example, the larger point was that you must always check. Best of Luck.

[poisondeathray]

No program detects what settings were used for encoding, and then replicates them precisely .

Video joins without issues, but the problem in your case is the audio headers in your samples prevent the audio from joining properly. Flac can be difficult to append. You would have to decode , join, re-encode the audio tracks. That should be lossless if done properly as it's decoded to uncompressed . Some audio programs might dither if you change bit depths, then that wouldn't be truly lossless

[haggis999]

No program detects what settings were used for encoding, and then replicates them precisely .

Video joins without issues, but the problem in your case is the audio headers in your samples prevent the audio from joining properly. Flac can be difficult to append. You would have to decode , join, re-encode the audio tracks. That should be lossless if done properly as it's decoded to uncompressed . Some audio programs might dither if you change bit depths, then that wouldn't be truly lossless

One of the assumptions I have been making is that I can trust MKVMerge to join together samples taken from the same original source (ignoring blank divider clips for the moment). Are you suggesting that this is not a safe assumption?

Any software that will do what you want will also create the black you need anyway. Check out TMPGenc Authoring Works.

I have installed the trial version of TAW but can't see any way to modify the video in a way that changes the actual image in a frame (none of the options in the Edit Menu seem relevant). In other words, it is not obvious how I could edit a selection of frames to make them all black. Have I missed something?

David

[smrpix]

I have installed the trial version of TAW but can't see any way to modify the video in a way that changes the actual image in a frame (none of the options in the Edit Menu seem relevant). In other words, it is not obvious how I could edit a selection of frames to make them all black. Have I missed something?

Just use a black still and stick it between your clips for 2:00 or whatever duration you want. You can fade to and from the black -- which may be sufficient on its own. It also has smart rendering to minimize quality loss which is why I recommended TAW instead of TMPGenc Video Mastering Works which is a little more flexible.

[haggis999]

Just use a black still and stick it between your clips for 2:00 or whatever duration you want. You can fade to and from the black -- which may be sufficient on its own. It also has smart rendering to minimize quality loss which is why I recommended TAW instead of TMPGenc Video Mastering Works which is a little more flexible.

As mentioned in my OP, I don't want to re-encode my primary extracts, so fade in/out will not be possible. However, re-encoding would not be an issue for a much shorter extract to be converted to a blank insert clip. Is there any editing program that would let me mess with the video in such a clip?

David

[smrpix]

TAW. Nobody's forcing you to use fades.

[haggis999]

TAW. Nobody's forcing you to use fades.

I realise that. Fades have already been faded out of this discussion

You appear to be reiterating that TAW is a viable solution for converting an extract from my Blu-ray rip into a plain black clip but I don't understand how to do that.

The whole point of starting with a clip from my original Blu-ray is to retain all the same video, audio and subtitle settings and thus make joining with my primary extracts a more straightforward matter. Unless I'm missing something here, importing a black still image into TAW doesn't appear to achieve that objective.

David

[haggis999]

Are you perhaps suggesting that I create my short divider clip by assembling a few frames from the end of one of my primary samples, a few frames from the beginning of the next primary sample and then stick a black still in between them (with fading to make it look better)? If so, does such a combination retain all the required video, audio and subtitle tracks?

David

[smrpix]

Not sure it will retain the subtitles. Makes the whole thing far more complicated.

[haggis999]

Some of my previous experiments using poisondeathray's black clip (which does not contain any subtitle tracks) suggest that subtitle tracks might not be vital in a divider clip.

I have been trying out what I suggested in my last post but have hit a problem trying to introduce a black section. I used TAW's Source Wizard to select a black colour matte but this was put on a second video track and the size was fixed at only 720 x 480. I couldn't find any way to increase this to Blu-ray dimensions.

David

[smrpix]

Maybe you can try to pull 2 seconds of black from the very beginning of the show before the first title.

[haggis999]

I was thinking along similar lines but, so far, all I have found is a single frame that is all black and I can't yet see any way to duplicate frames in a clip.

David