occasional stutter on video input

[ajmaudio]

using a blackmagic extreme for composite input on a tour... works flawlwess most of the time but every now and then I get a few seconds of jerky video then all is normal again. I cannot be 100 percent sure at this point that it is my catalyst but I assume that the ledpros driving our slight are not causing this. anyone have any thoughts? anyone had any issues at all like this? its very random and I have not been able to see this happen on the catalyst itself.

[samsc]

using a blackmagic extreme for composite input on a tour... works flawlwess most of the time but every now and then I get a few seconds of jerky video then all is normal again. I cannot be 100 percent sure at this point that it is my catalyst but I assume that the ledpros driving our slight are not causing this. anyone have any thoughts? anyone had any issues at all like this? its very random and I have not been able to see this happen on the catalyst itself.

i have seen problems like this with specifically the composite input on a decklink extreme- on a tour last year- didnt seem to affect the sdi input.

can you get the sdi input to work and compare?

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but in these systems there are lots of sources of these things.

[ajmaudio]

Not sure that I will be able to do that while we are out on tour... I'll try... I looked on the Black Magic site and found a new firmware release that fixes genlock stability and general stability and performance but when I called them they said they had no reports of issues like mine. I'm not certain that a genlock issue would look like this.. though it may in the digital domain once the signal is "in the card". As far as other things that may cause this... are there any system tweaks or other things anyone can recommend taking a look at... the system is flawless aside from this issue and I'd like to get it rectified asap.. thanks

[rosswill]

Out of interest what is your system configuration and s/w versions?

Ross

[ajmaudio]

m165, 2.8ghz 8 core mac pro, decklink hd extreme2 running latest os... anyone using this card with or without the same problems??? The new firmware revision for the decklink card does not seem to have rectified the problem... it MAY be less severe but its been hard to observe. I ahve contacted them and they have supposedly heard no similar reports during usage of the composite inputs. I dont have access to a converter to use the SDI input at this time but if this is a definite solution I will get one asap.

[rosswill]

I have reported a similar issue to Richard this week with playback of content from the SSD drive. I wonder if it's not actually the Decklink but something else like the OS, QT or graphics card.

Regards,

Ross

[NevBull]

I have had a similar problem with the Decklink installed - content streaming from the SSD drive would occasionally stutter when starting playback. This problem went away when the Decklink card was removed from the machine.

[rosswill]

For me it was mid playback and not when playback started.video input not switched on although Decklink card present.Ross

[ajmaudio]

Im only having issues with the actual video input as far as I can tell... my ssd playback seems to be fine though perhaps it could be better as all of those components were installed at the same time. does anyone know if perhaps the video is buffered " off the card" perhaps to the system drive for QT to do its thing? This is starting to be a serious issue for me... any and all ideas are appreciated. With all the reading I did it seemed that the decklink card was a no brainer thats what kills me lol

[ajmaudio]

do any of you guys NOT have your card installed in slot 4??? afer some research its supposedly the best option... these newer 08 mac pros no longer use the expansion slot utility to set the speed of the slots.. they are permananty asigned their "lanes" turns out mine is installed in a PCIe 2.0 slot ... changing slots will be my next move... surely it isnt that easy?? anyways.. question still stands.. any of you have your cards in a slot other than number 4?

[samsc]

do any of you guys NOT have your card installed in slot 4??? afer some research its supposedly the best option... these newer 08 mac pros no longer use the expansion slot utility to set the speed of the slots.. they are permananty asigned their "lanes" turns out mine is installed in a PCIe 2.0 slot ... changing slots will be my next move... surely it isnt that easy?? anyways.. question still stands.. any of you have your cards in a slot other than number 4?

suggest you make every attempt to try sdi input on decklink card.

[samsc]

For me it was mid playback and not when playback started.video input not switched on although Decklink card present.Ross

not related to this thread.

[Mr_P]

Ive not seen any evidence of deckink cards specifically causing content to stutter - in use or not in use. ( What tests have people performed to arrive at this conclusion?) This is a separate issue from the stutter seen when using the video input of a decklink card.

I know that decklink cards DO frame buffer. I have timecoded video footage to prove it, taken when using SDI capture on an HD Extreme (although not composite). Buffering seems to happen more when other operations are occurring in the Mac. Also more prevalent on HD-SDI capture as it requires more bandwidth.

With regard to PCIe slots - 2007 & 2008 Macs have different PCIe architecture and will work and be configured in different ways. 2007 macs running tiger can use the PCI expansion slot utility. 2008 Macs running Leopard cannot. However, on 2008 Macs, the bandwidth/lanes is 'dynamically' allocated - depending on the card installed and slot. Bandwidth is not necessarily 'fixed'

With 2008 MacPros running Leopard, the slot next to the graphics card is the fastest PCIe2 slot. However, it shares its 'communication' with the 'north bridge' controller along with the graphics card. The Upper 2 PCIe slots share the 'South Bridge' controller with the Firewire controller and optional Airport Module. Any of these devices 'could' affect performance of the decklink card causing it to frame buffer - depending on which slot it is installed.

However, a decklink Extreme HD card is only a 4Lane PCIe1 card, so does not need to be installed in slot 2 which is a PCIe2 slot.

for more info - check out:
http://developer.apple.com/documentation/Hardware/Conceptual/HWtech_PCI/Articles/pci_implementation.html

There are 3 different issues being reported here - so don't confuse, decklink 'frame buffering' with 'content playback stuttereing' and differences between the 'composite and SDI' inputs.

Better still - use an Active silicon LFG or Phoenix card.....

Simon

[ajmaudio]

I'm not confusing the different issues being discussed here... unfortunately I cannot count on being able to use the sdi input on the card.. and honestly id rather get to the bottom of this issue as this device works just fine capturing composite video outside of this. Can anyone tell me if any of the video is being buffered outside of the decklink card itself? I'm hoping moving the card will solve this issue but since Richard has had this issue and I dont know anything about that particular machines configuration I am not all that hopeful. so as of now the new firmware hasnt resolved the issue though PERHAPS lessened it and I wont know about moving the card until saturday at the next show. Is anyone NOT having this issue with this card?

[Mr_P]

Decklink cards are designed primarily for use in NLE systems where every frame is required to be captured (from a deck) and 'real-time' does not matter.The Deckink Card has the ability to buffer frames built in, so that none are lost when transferring footage from deck to timeline. Nothing outside of the decklink card buffers frames. Decklink drivers do not give access to turn off this feature - and it is not something that can be turned off by a firmware update or within Catalyst Software. This card is not specifically designed for 'LIVE' use - as is the nature when used with Catalyst Software

Decklink just sell cards 'as is' - they dont support or communicate with Software designers.

The random nature of when a decklink card buffers frames is an issue that cannot be resolved. Users can streamline their systems as best as possible to ensure that sufficient bandwidth is available and cross your fingers that the card will not need to buffer any frames. Its a bit of trial end error to see what works for you.

For all the reasons above, this is why time and effort has been spent working with Active Silicon to develop capture cards that do not buffer the video input. Richard has worked very closely with AS to write drivers and ensure that their LFG and Phoenix cards have the lowest latency possible and that no video input is buffered.

The cost of an LFG4 (composite) card is less than that of a Decklink HD Extreme. The dual input Phoenix 2xSDI card (when available) is about the same price as 2xDecklink HD Extreme.

I would always recommend setting aside enough 'prep' time - outside of your production - to test and ensure that any of these cards to operate in the manner in which you expect them to perform...

If you require any assistance, do contact me.

Simon

[samsc]

you need to try the sdi input ( not the composite input )- you need to get a convertor-

nothing else here is relevant until you try this- forget everything else

there are many devices which do this:

this is one ( im not recommending this - im saying this is one of many devices )

http://www.aja.com/html/products_converters_D10AD.html


I'm not confusing the different issues being discussed here... unfortunately I cannot count on being able to use the sdi input on the card.. and honestly id rather get to the bottom of this issue as this device works just fine capturing composite video outside of this. Can anyone tell me if any of the video is being buffered outside of the decklink card itself? I'm hoping moving the card will solve this issue but since Richard has had this issue and I dont know anything about that particular machines configuration I am not all that hopeful. so as of now the new firmware hasnt resolved the issue though PERHAPS lessened it and I wont know about moving the card until saturday at the next show. Is anyone NOT having this issue with this card?

[samsc]

this is not relevant to the technical problem- until he tests the sdi input - not the composite input.


Decklink cards are designed primarily for use in NLE systems where every frame is required to be captured (from a deck) and 'real-time' does not matter.The Deckink Card has the ability to buffer frames built in, so that none are lost when transferring footage from deck to timeline. Nothing outside of the decklink card buffers frames. Decklink drivers do not give access to turn off this feature - and it is not something that can be turned off by a firmware update or within Catalyst Software. This card is not specifically designed for 'LIVE' use - as is the nature when used with Catalyst Software

Decklink just sell cards 'as is' - they dont support or communicate with Software designers.

The random nature of when a decklink card buffers frames is an issue that cannot be resolved. Users can streamline their systems as best as possible to ensure that sufficient bandwidth is available and cross your fingers that the card will not need to buffer any frames. Its a bit of trial end error to see what works for you.

For all the reasons above, this is why time and effort has been spent working with Active Silicon to develop capture cards that do not buffer the video input. Richard has worked very closely with AS to write drivers and ensure that their LFG and Phoenix cards have the lowest latency possible and that no video input is buffered.

The cost of an LFG4 (composite) card is less than that of a Decklink HD Extreme. The dual input Phoenix 2xSDI card (when available) is about the same price as 2xDecklink HD Extreme.

I would always recommend setting aside enough 'prep' time - outside of your production - to test and ensure that any of these cards to operate in the manner in which you expect them to perform...

If you require any assistance, do contact me.

Simon

[Mr_P]

ajmaudio - Did you get to the bottom of this issue?
What tests did you do - what did you find?
Simon

[ajmaudio]

well being on tour and having 3 jobs on said tour didnt leave much room for tinkering... we managed to get away with it as it was a rock show and nobody seemed to notice.. however I have a more corporate type for new years and I dont think this performance is going to be acceptable. I also noticed that someone else was having this same problem even using the sdi input on this same card. At this point I just wish I coudl trade this card for an LFG though it seems that this issue should NOT even be happening purely based on what this card is used for normally. Seems like its gotta be solvable but then I dont know. I only have the stock 2 gigs of ram in this machine but while checkin memory usage during use I find that well over half of the actual ram is still available to the machine.. that was my last thought on the issue. anyone else made any headway?

on a side note if anyone has an LFG card that I could rent in the nashville area id be interested.

[samsc]

i had a very good reason for suggesting what i said-

i saw a problem with the composite input on the card last year - it only affected the composite input- not the sdi input- there was some problem with this - i have no idea the cause-

this is not related to anything anyone else was discussing on this thread-

there are a whole bunch of other issues with video input- and computers but the composite problem with sdi input cards is the first that needs to be checked.
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ask mainlight about LFG cards- and whether you can loan one-


well being on tour and having 3 jobs on said tour didnt leave much room for tinkering... we managed to get away with it as it was a rock show and nobody seemed to notice.. however I have a more corporate type for new years and I dont think this performance is going to be acceptable. I also noticed that someone else was having this same problem even using the sdi input on this same card. At this point I just wish I coudl trade this card for an LFG though it seems that this issue should NOT even be happening purely based on what this card is used for normally. Seems like its gotta be solvable but then I dont know. I only have the stock 2 gigs of ram in this machine but while checkin memory usage during use I find that well over half of the actual ram is still available to the machine.. that was my last thought on the issue. anyone else made any headway?

on a side note if anyone has an LFG card that I could rent in the nashville area id be interested.