After much testing, I could not foresee any technical reason why the Second or ‘B Channel’ of vMix Replay could not be controlled (play, pause, jog, shuttle) using an external control surface. This feature would add considerable value to any sports production. There were no issues in throughput to encode four HD-SDI channels and playback two HD-SDI channels simultaneously using the 2TB WD Caviar Black HDDs. Even less of an issue when using the SSD drives, as would be expected. Windows Task Manager reported 25-35% CPU usage when in this six channel mode vMix Replay mode. The vMix Replay logs reported no problems, nor the statistics dialog (Source dropped = 0, Render dropped = 0, Resync = 0), which is very pleasing.

In this scenario, with four HD-SDI inputs being recorded at 1920x1080 i50, 100mbps and the vMix Replay applet with both A & B synchronized in playback mode, I added an additional video input which accessed the recording file (MPEG-PS) for the first channel and commenced playback. Then a second video playback of the second vMix Replay channel, and so forth to stress test the computer system and the MPEG encoders/decoders. Seven video record/playback channels appeared to be the limit, which in itself is impressive for a software based video production system.

The sources used for the tests were four DVB-T tuners/receivers connected to four HDMI/HD-SDI converters, and then fed to the BlackMagic Decklink Duo2 (4 Channel input) video card. It was important to use video sources that provided complex encoding scenarios, for the tests to be valid in the real world.

Having read through all the Posts in the ‘Instant Replay’ section of the Forum, which by the way provided a great insight to a broad range of requests, it would seem that this ‘B’ channel feature is important to many Users. Thanks to curtismacd31, stevespaw, tomotom1976, jens, HighViewSport, Rinsky and admin for the providing their thoughts on this subject.

It would be beneficial to vMix and its Users to have this feature, with the covenant that the PC system must be moderately spec’d to provide the resources needed to facilitate this feature. The responsibility of which is wholly that of the User, and not a reflection on the performance of vMix.

To add this feature to vMix Replay, would not require much in the way of additional coding. The features and workflow would remain for the most part as it is currently. The automation stays in place. The only addition would be those related to the system shortcuts/api for Instant Replay. These would include, but not limited to:

B_ReplayChangeDirection
B_ReplayChangeSpeed
B_ReplayJumpFrames
B_ReplayJumpToNow
B_ReplayPlayPause
B_ReplaySetSpeed
B_ReplaySetDirectionBackward
B_ReplaySetDirectionForward
ReplayABSynchronized (Description: Toggle Replay A+B synchronised On/Off)

All other operations and functions would be performed using the ‘A’ Channel or the ‘Events’ grid/dialogue. Essentially, the feature request is about controlling the ‘B’ Channel for playback of replays at a point in time of the User’s choosing, whilst in the Manual mode. Transitions between the ‘A’ and ‘B’ channels shall be performed manually, either directly on the vMix interface or remotely via a control surface and shortcuts.

The system specifications on which the tests were performed are: Z170 motherboard, i7 6700 3.4GHz Quad Core processor, NVidia 4GB GTX960 video card, 16GB 3000MHz RAM, 2 x 500GB Samsung SSD and 2 x 2TB WD Caviar Black HDD. HD-SDI capture and playback courtesy of BlackMagic Decklink Duo2 (4 Channel input) and Decklink SDI (2 Channel output). Control surface is a Behringer PL-1 and touchscreen.

Currently we have vMix 4K (single channel replay), and wish to upgrade to vMix Pro and version 18 when released, but with no control of the vMix Replay ‘B’ channel, it is a deal-breaker. Martin, I hope that you are able to embrace the workflows that many of your customers are presently using with other replay systems, and the expectation of Directors/Producers in providing such replays.





Above: vMix with seven simultaneous video channels.

Some of the forum sources for the vMix Replay control of the second channel (B) feature request:

“ ... . independent operating at channel A,B and A+B”
http://forums.vmix.com/d....aspx?g=posts&t=3889

“My thoughts would be that output A and output B need to be independent. This would allow the operator to cue up one replay in output A and then allow them to cue up another replay in output B even while output A is playing out. “
http://forums.vmix.com/d....aspx?g=posts&t=3340

“ ... Mainly need a true second channel.”
http://forums.vmix.com/d....aspx?g=posts&t=5774

“Sounds logical, but a 2 channel output replay system would also have huge advantages. You could rewind and create another event in channel B while an already created event list is playing in channel A.”
http://forums.vmix.com/d....aspx?g=posts&t=3340

“ ... Already mentioned the more common PGM/PVW mode: Standard is you control both outputs, jog to a good In-point for your replay, press "PVW" button, the PGM stays at your In-point waiting for your lever to start that replay - while you can jog with your PVW channel to a different angle or position on your recording. If you want to play your PGM replay just move the lever (T-bar), and if you´re finished press "Take" and your PVW replay switches/fades/wipes (changeable in Settings on the EVS) to the PGM output. And you´re still in PVW so you can easily cue up the next replay while PGM output is still playing out your second replay clip.”
http://forums.vmix.com/d....aspx?g=posts&t=3889

Your support for this feature would be most welcome (+1).

Do I understand this the right way? You want Channel A to be controlled by the "normal" Vmix operator and Channel B to be controlled seperately by another person?

With this workflow the Vmix operator could make fast replays on his own, while the replay guy produces highlight reels and some more specific stuff. Of course there needs to be a good control panel for this to make it work as seamlessly as it sounds, but it would be a great thing for bigger live productions.


BUT...when using channel A and B as two independent channels, they need to use the same recorded video files at the same time, but at different frames (and all that with all replay inputs) or should this be achieved by recording every input twice?

Channel A should be able to switch the camera inputs/angles, just as channel B should be capable of doing that, which means that there are 8 requests on 4 video files at the same time, if I understand it correctly.



There are other things that I'd prefer to be included than an independant 2nd channel, things like:


• Having more than 4 inputs (I would be happy with 6)

• Seeing all 4 (or 6) inputs at the same time (1 row with the recorded video material and another with the live input just beneath it)

• Beeing able to scroll backwards from the live input, without have "go to recorded mode". I know that the recording is not as fast as the live input and is always a few frames behind, but it's not 1 second (as Martin said in another thread) it's just a few frames and I think that every replay operator could handle that lag.

• Seperate shortcuts (and UI buttons to click) for creating an event of the last 5,10,20 seconds of live and another for the last 5,10,20 seconds of where my cursor/my recorded footage window is right now. This way I could create an event of the live footage asap if something important happens while fuddling around with other events on the recorded mode.

• Extend the export function with social media exports and export in another file format like .mp4.

• Ability to create more event lists and name them

• Get rid of giving each camera angle a name, I'd rather give an event a name then a camera angle, because I already game my camera angle a name and if one of my cameras capture something completly different at the same time, then I will create another event and name it accordingly. Those blank spots take up too much space when using instant replay in a not detached way. Space that could be used for another column for predetermining the events replay speed.



I think that those features a more basic and fundamential than a 2nd channel and (hopefully) easier to accomplish. Don't get me wrong, I would love to see that someday, but I don't think that this will be available anytime soon, but Martin could build the basics that this workflow will work someday.

Oh yeah, and another thing I'd like to see someday is the ability to predeterminate replay speeds within an event, let's say an event is 15 seconds long and I want it to be player with 75% speed rate at first and after 5 seconds (e.g. someone takes a shot, catches a ball, or whatever) I want it to slow down to 33% and after 10 seconds it should be back to 75%. This way we could create perfectly timed highlight reels within Vmix, something a seperate replay (Vplay? I like that term, also thought about that a long time ago. You should trademark it, Martin) could do, while the normal Vmix operator works on basic replay, during live production.


Sorry for hijacking, but I still hope that I contributed to your thread somehow.

Regards,
Patrick

Quote: “Do I understand this the right way? You want Channel A to be controlled by the "normal" Vmix operator and Channel B to be controlled seperately by another person?”

Appreciate the feedback. Never thought of that scenario for vMix Replay. Simply put, to give a ‘single’ replay operator or director the flexibility to manually choose, and cue-up the next replay angle using the ‘B’ channel, and then mix manually using the standard vMix interface. For example, in a football match, the sequence of replay angles may include: 1. The wide shot of the last play to the match try/goal. 2. A low angle shot of the last few seconds of the try/goal being scored. 3. A mid shot of the reactions of the scoring team players. Each of the three angles would be cued-up at a different point in time. The operational sequence would be: 1. On ‘A’ cue-up the wide shot of the last play to the match try/goal. 2. Mix to Channel ‘A’. 3. Cue-up on ‘B’ the low angle shot of the last few seconds of the try/goal being scored. 4. Mix to Channel ‘B’. 5. Cue-up on ‘A’ the mid shot of the reactions of the scoring team players. 6. Mix to Channel ‘A’. 7. Replay sequence complete. Mix to Live Camera.

All this is achieved by using an external controller like the Behringer PL-1, X-Keys or any other suitable device, using vMix shortcuts. The existing automated method would still be available, but rather the operator/director would have the choice of either manual or auto operations. So it’s only about adding shortcuts to facilitate this requested feature. The vMix Replay interface would remain the same. Both the Replay ‘A’ and ‘B’ channel players already exist within the interface, so the CPU/GPU resource usage should not change significantly. This was verified in my testing results.

Incidentally, I coded in .Net the commands for four channels of recording in FFMPEG, and used the FFOCX SDK to output all four replay channels into two Z-Order PictureBoxes, and switched between them to see how the resource usage would impact on my system. The results were similar to those of Martin and Tim, in fact theirs were better. So some good coding going on at Studio Coast & vMix. Parochial as it may seem, I would rather support their efforts in this regard.

We are in the same situation Steve, and sense many other vMixers have the same dilemma. To hire a 3Play 425, when vMix Replay is so elegantly simple to set-up and operate surprises many of the replay operators. No to mention out of the vMix system they can play any other multimedia using various other inputs, and having the built-in vision mixer is a real advantage. All are left puzzled as to why.

The mystery of the vMix Replay ‘B’ Channel. What is its purpose? There’s no explanation in the written documentation or the video demonstration.

It looks like a ‘B’ Channel, plays like a ‘B’ Channel, but doesn’t act like a ‘B’ Channel. It just plays in sync with the ‘A’ Channel consuming resources.

When performing an automatic replay ‘Play Events” sequence, all the camera angles are output and mixed via Channel ‘A’. Channel ‘B’ again just rolls in sync. There’s no look-ahead feature on Channel ‘B’ to compliment that sequence on Channel ‘A’ when performing a “Play Events” sequence. Interesting behaviour, unlike any replay system I’ve encountered.

Hence the request for a more cohesive and normalized workflow, for which most operators are familiar. Control of the ‘B’ Channel is fundamental in every way imaginable. At $US850 It’s a quantum leap to jump from the HD version to the Pro version with vMix Replay without this facility. Personally, I would rather promote and invest my dollars in vMix, not because it is potentially a great product, but rather, because it IS a great product, with great support.

Thanks IceStream. It was certainly good reading the early posts during the development phase of vMix Replay, and the collaborative effort between the forum members and Martin. It wasn’t until mid-2015, while doing other research, that I discovered by accident this software called vMix. Downloaded the 60 day trial a few months later, and with the upcoming vMix 17 and the inclusion of NDI amongst other features, decided to purchase. Sadly most of the development of the replay module had been completed.

One snippet I did find was a mention from Martin regarding the issue of simultaneous encoding/recording and playback of four I/O channels of HD. Ambitious to say the least, hence his adjustment of the specifications:

@Admin 19 Jan 2015. “One change that has been made since the preview screenshot, is the removal of the Quad camera playback preview for performance reasons. Instead two simultaneous camera angles can be displayed and you can pick any of the four angles to show on each. Recordings show up as two constantly updated inputs Replay A and Replay B. Pick any camera angle for each and use one or both just as you would any other input.”

Herein lay the reason for the synchronised playback of the A & B Channels. The coding, display and output appears to be already in place. What is needed is a checkbox in vMix Replay setup to un-synchronise the A and B channels. Two modes of operation: A+B (synchronised outputs) or A&B (distinct outputs). Plus the below mentioned shortcuts to permit control of the B Channel. Essentially a duplication of existing shortcuts with the prefix “B_” assigned to the B Channel player.

B_ReplayChangeDirection
B_ReplayChangeSpeed
B_ReplayJumpFrames
B_ReplayJumpToNow
B_ReplayPlayPause
B_ReplaySetSpeed
B_ReplaySetDirectionBackward
B_ReplaySetDirectionForward
ReplayABSynchronized (Description: Toggle Replay A+B synchronised On/Off)

This feature along with the additional Event Lists will be a game changer. This is the moment. vMix 18 Replay can change the landscape of sports broadcasting and streaming forever.

I would love to see independant control for A & B channels.