Reduction of audio channel bitstream to 5.0 (not 5.1) by VRD 5 and 6


New member
I have an issue where VideoReDo is rendering DTS-HD MA and Dolby Digital audio bitstreams of 5.1 or more channels from MKV videos to 5 channels.

Since 2014, I’ve been using VideoReDo v5 to make trims of MKVs containing Dolby Digital and DTS-HD MA bitstreams with 5.1 audio channels or more and in my final edits rendered by VRD, the edited bitstreams contains the same number of channels as the originals.

However, last Saturday, January 18, was different. I’ve made some MKV clips from a video with 5.1 channel DTS HD MA and Dolby Digital bitstreams. When I load the clips into MKVToolNix, the software indicates that the bitstreams of each clip is 5 channels, not 6 channels—the ‘.1’ is considered one channel, although the software still identifies the bitsteams as DTS HD MA and Dolby Digital. image.png

Also, In MediaInfo where compared the bitstream’s specs between the original MKV video file and the small clip from that video rendered by VideoReDo, this is what I found.
image (1).png

The last time I’ve used VRD was January 1 and on that day, the 5-channel-bitstream problem didn’t occur. I suspect that there was something in the software programing that caused this incident to occur at the start of 2020.

I brought this problem to VRD support on Sunday. The next day, Monday, support responded by giving me a trial version of VRD 6 and asked if this solves the problem. I installed VRD 6 in my computer and made a clip of the same video with the DTS and Dolby Digital bistreams in 5.1 channels. I loaded the clip into MKVToolNix and MediaInfo, and the same problem exists—the information indicates that the bitstreams are in 5 channels. I’ve reported my findings to support on that same Monday afternoon. No response from support. Wednesday, I’ve sent support a follow-up email to inquire if they made any progress on my problem. No response.

Now, I bring my problem to the forum members. If this has happened to you, please let me know how you have solved it.

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Ex-Senior Developer
We haven't changed the DTS portion of VideoReDo in a looooong time, so this is more likely an issue with MKVToolNix than VideoReDo. Also our DTS support is passthrough only, meaning we can only output what we get in. We have no ability to alter the DTS audio internally. So it's physically impossible for us to have removed the .1 from the DTS stream and have it still be DTS. If we had recoded the audio it would be 2ch and it would be either MP2 or AAC as those are the only encoders included in the product. (v6 does support 5.1 AC3 audio, but your screen shot is showing the file as still being DTS so it's not being recoded to AC3 either)

There is a notice in the corner there saying a new version is available. Maybe try updating and see if that fixes the issue.


New member
This thread seems like a relevant place to post this query (sorry if it is not);
Using VideoRedo TVSuite 5, I've been trimming TV programmes and obviously HD ones I save in .MP4/h264 as my hardware players seem OK with this.
For a long time I cut movies from UK Freeview Channel4 at the video fade point. When I came to play them, some devices would mute the sound after the cut ad break, or rather it would be without dialogue. By stopping the movie, and navigating to the just after the cut point, the dialogue track would then be played.
I noticed on the thumbnail audio, a change from yellow to blue, several frames before the video fade. Setting the cut point on the last yellow frame, is the workaround I currently use.
Is there a setting or update I can use, to cut at the video fade and still have audio dialogue return after the cut point? Ideally by converting 'blue' audio track to the 'yellow' format.



That sounds very much like something I opened a ticket with support [#MTE-97766-553] about nvingo if I'm not mistaken. My current workaround has been to manually set the audio output instead of leaving it on Automatic.


New member
Thank you, first test of that is positive.
I've set up a profile with that setting, for when audio change and ad-break cut points aren't aligned.
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