Rank: Advanced Member
Groups: Registered
Joined: 2/27/2013(UTC) Posts: 312   Thanks: 8 times
Was thanked: 78 time(s) in 43 post(s)
|
How does vMix measure drop frames within the normal statistics window?
The reason I ask is that 2 out of 3 of our cameras are going HDMI over cat5e cable and I am trying to eliminate links in the chain where loss could happen. If the HDMI extenders drop frames, would that show up as a dropped frame within vMix? For instance, if vMix is expecting 1080p60 and the HDMI extender only supplies 39 frames in a given second, would vmix report that as 21 dropped frames?
|
|
|
|
|
|
Rank: Administration
Groups: Administrators
Joined: 1/13/2010(UTC) Posts: 5,208 Location: Gold Coast, Australia Was thanked: 4288 time(s) in 1520 post(s)
|
In the Statistics window the follow columns are shown: Source Dropped-Capture card is unable to deliver frames fast enough Renderer Dropped-Graphics card unable to render frames in a timely manner Resync-Camera clock running faster than the system clock. Video33 33 33 33 (49) In the above example, the four previous frames arrived 33 milliseconds after each other indicating a frame rate around 30fps The number in brackets shows how long it took for the frame to displayed on screen. 1.5 frames in this case. Examples1. High Source Dropped, low Renderer Dropped Capture card dropping frames 2. High Renderer Dropped, low Source Dropped, resync may also be high. Graphics card dropping frames, check Render Time value at bottom of vMix. Times consistently above 20ms is a cause for concern. 3. Both renderer and source show large number of dropped System under heavy load, perhaps a particular input or recording is consuming greater than 80% of CPU. May also be caused by DPC latency issues. (A bad driver can hold up all other drivers on a system, causing delays across all types of hardware) LatencyMon is a good tool to diagnose DPC latency issues. http://www.resplendence.com/latencymon
|
 1 user thanked admin for this useful post.
|
|
|
|
Rank: Administration
Groups: Administrators
Joined: 1/13/2010(UTC) Posts: 5,208 Location: Gold Coast, Australia Was thanked: 4288 time(s) in 1520 post(s)
|
In addition to the above overview, to answer your specific question, it depends on the capture card.
Some cards will deliver the exact number of frames per second regardless of the source camera
others will deliver verbatim what they receive, missing frames and all.
Others still will show black frames if frames are being dropped by the camera (or cabling).
However, I have not seen Cat5 extenders cause dropped frames necessarily.
They may cause dropouts or "jumpy" and distorted images, but not a consistent amount of dropped frames.
In any cause, SDI cabling is highly recommended for long cabling runs.
An HDMI to SDI converter can be placed on one end and a SDI to HDMI on the other.
Converters can be found on ebay for around $200 for both. Or high quality converters from AJA are also available.
This is not to say this will solve your problem, but is good practice in any case.
|
|
|
|
|
|
Rank: Advanced Member
Groups: Registered
Joined: 2/27/2013(UTC) Posts: 312 Thanks: 8 times
Was thanked: 78 time(s) in 43 post(s)
|
Thanks Martin! That's all really good info. I never realized what those four numbers meant. Now would numbers that very drastically in those set of four numbers indicate some sort of bad clock or capture car? In good video capture should all those numbers the fairly consistent? If those numbers vary greatly will the resulting video seem more choppy?
If there is an issue with the capture card not being able to pass the frames fast enough, can a buffer be added to compensate? One of the issues I am having is with a new capture card I am testing. I seem to be getting a great amount of drop frames but when viewing the video live In vmix I can't really tell if many frames are being dropped if any at all. How would it be possible to have a lot of dropped frames logged but not seem as if framed are being dropped in live video preview?
I'll try to get a log and some video up soon.
|
|
|
|
|
|
Rank: Advanced Member
Groups: Registered
Joined: 11/30/2013(UTC)
Posts: 165
Location: Seoul, South Korea
Thanks: 39 times
Was thanked: 19 time(s) in 14 post(s)
|
Thanks Martin! Can this information be written in the vMix documentation for version 13? Thanks!
|
|
|
|
|
|
Rank: Advanced Member
Groups: Registered
Joined: 2/18/2014(UTC)
Posts: 1,837
Location: Stockholm
Thanks: 144 times
Was thanked: 297 time(s) in 250 post(s)
|
Is perhaps "source" frames "dropped" in large numbers when the source frame rate is higher than the frame set in vMix?
|
|
|
|
|
|
Rank: Advanced Member
Groups: Registered
Joined: 2/27/2013(UTC) Posts: 312 Thanks: 8 times
Was thanked: 78 time(s) in 43 post(s)
|
Did some more testing.
When I changed the capture settings to 30p instead of 60p, I get about 1 or 2 drop frames in total.The input coming into the HDMI port is still 60p but I changed the capture settings to 30p. This is strange because the capture input is not half the rate of the system frame rate. I thought that if the system and the capture device is different, that would result in dropped frames.
When I add a second camera from the same card at 30p I start getting dropped frames again.
When I was capturing in 60p, the 4 numbers were right at about 14 14 14 14. Is that normal with a 60p input?
|
|
|
|
|
|
Rank: Advanced Member
Groups: Registered
Joined: 2/27/2013(UTC) Posts: 312 Thanks: 8 times
Was thanked: 78 time(s) in 43 post(s)
|
I think I figured out most of my problem.
So for any of you out there using the ASUS Maximus Hero VI, the bottom PCI-e slot on the motherboard is by default set to 1x and switchable to 4x by disabling the other 1x slots. I was trying to use a 4x card in the 1x mode. Why a 4x slot has the physical slot of a 16x, I do not know. Hopefully this saves someone some time!
|
1 user thanked thecloudmediagroup for this useful post.
|
|
|
|
Rank: Advanced Member
Groups: Registered
Joined: 2/27/2013(UTC) Posts: 312 Thanks: 8 times
Was thanked: 78 time(s) in 43 post(s)
|
Another question on frame rates;
Are the 4 bracketed number in the stats window indicitive of any kind of video jitter or stutter? In testing some video, sometimes I seem to get the feed looking like it is skipping some frames or not displaying them symmetrically from each other. In such cases there are no drop frames or render drop frames either.
|
|
|
|
|
|
Rank: Advanced Member
Groups: Registered
Joined: 2/18/2014(UTC)
Posts: 1,837
Location: Stockholm
Thanks: 144 times
Was thanked: 297 time(s) in 250 post(s)
|
thecloudmediagroup wrote:the bottom PCI-e slot on the motherboard is by default set to 1x and switchable to 4x by disabling the other 1x slots. I was trying to use a 4x card in the 1x mode. Indeed very valuable info - thanks! How did you find that out (info in the mobo manual)? And, did you do the disabling in the bios?
|
|
|
|
|
|
Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.
Important Information:
The vMix Forums uses cookies. By continuing to browse this site, you are agreeing to our use of cookies.
More Details
Close
