Hi, thanks for reading my post.

I've tried searching for a solution to this but I'm not sure if it is possible, I'm hoping someone could advise please.

My vMix (latest update) will play many MP4 video clips with no issue but it seems unable to cope with certain MP4s (I get audio with black screen).

The interesting thing is that the clips that don't work play fine on the same computer using VLC or Media Player.

I'm fairly confident that these apps have an MP4 codec that vMix doesn't.

My question is can I update the codecs that vMix uses?

In vMix settings MP4 is currently on the list to use the FFMPEG decoder. However, I've also tried removing it from the list and still have the same issue.

I assume when it is removed from the list it looks for a Windows decoder? I was hoping that it would find the ones that VLC or Media Player are using although perhaps they are built in to those apps and not accessible?

Is there any way to allow vMix to access a wider / newer selection of MP4 codecs?

Many thanks for any advice!

Thank you for your reply.
I tried removing *.mp4 from ffmpeg which didn’t solve it so I added it back again before trying anything else.
I also read about changing to EVR and tried that too which didn’t solve it so I changed it back.
However, I didn’t try both changes together, just 1 at a time.
I will now try both changes together although from your post you are advising caution as it may create other problems.
Many thanks.

Thank you for your reply Martin.
That sounds like exactly the problem we are having.
I have found that the Handbrake app can modify the problem files to a format that vMix seems to be able to handle with little loss of quality.
I don’t know if that will work every time and it’s an extra step but hopefully that will help until there is a codec update.
Thank you.

Thanks.
Yes, I found the codec info on VLC. I can’t remember exactly what it said, I’ll check later, but it listed 2 codecs. I think it said stream 1 and stream 2. Maybe video and audio separately?
You’ve said what I have been thinking. It does play fine on Media Player so the correct codec must be somewhere in either Windows or Media Player.
Is there no way to force vMix to use existing codecs on the computer as a useable codec must already be there?
If I add the H265 codec that should help? Would that just be installed into Windows then vMix would find it?
Although presumably that codec it is already accessible to Media Player as it is capable of playing the video yet vMix cannot use it at the moment.
Thank you

Hi. In my personal opinion this FR allready exist twice https://forums.vmix.com/...-Hardware-Video-Decoding and https://forums.vmix.com/...re-video-decoding-on-GPU
and i hope in Vmix 29 you will add it
This FR at my personal opinion is going together with HW video decoding option. It is somehow funnny to have the best GPU and rely and load CPU in order to play a video

Hi.
I’ve looked at the problem videos again using VLC and it does indeed identify the video codecs on these as av01 as suggested in an earlier reply.
Thanks to everyone for your suggestions. I think if this happens again I’ll just try to convert them.
Hopefully a future update will add this codec to vMix.
Thank you.