Glimmie, I am not going to get into a long technical drawn out debate over the merits of technical specs vs audible/visual differences you cant measure. I agree with you that yes, there are companies with little if any technical merit selling cables like snake oil. However there are also companies who actually use Belden R&D and Belden manufacturing to make cables. There are cables that make a difference. Besides,, the conversation is off topic and is best suited to a separate thread. Honestly I dont have the time to debate this 20 year old battle.
Yes that's absolutely correct. But science does not back up that jitter in a multiplexed packetized stream will just affect one of the streams. It will affect all the streams.
And the audio stream jitter might be more perceptible then any video jitter.
Again in HDSDI and HDMI the audio is packetized in non real time. Any cable induced jitter will effect the video just as it will the audio.
Yes but again the perception of the audio jitter may be far more noticeable then the video jitter.
Does the quality of your Ethernet cable matter for music downloads? I'm sure there are charlaton cable vendors that say it does but once again it's hogwash. And you can't say that's low end audio. It may be from some sites like "YouTube" but there is no reason you can't send full 24bit 192khz over the internet. It just depends on how long you are willing to buffer and wait for the complete file.
with the file downloaded clearly the cable jitter no longer exists. However if the cable introduces some packet loss and retransmission, and this does happen for sure, then on a streamed audio feed with a D/A process with little if any buffer then obviously you would hear the difference.
Also consider that if HDCP is in use, the data is scrambled. So ANY data recovery error will cause a complete packet loss. This is why non-HDCP links just have lots of sparkels on a margional link while an HDCP link will "blue screen" for a second or longer.
Its not about each decrypted packet of data, its about how evenly the stream of packets comes thru and gets decoded. How much stop/start. How much jitter in the decoding of the whole stream, decrypted and all..
You do have a interesting point I had not considered. Does HDCP have better/worse sound then non-HDCP... Interesting thought... I would have to go back to the standard and read up on how it was encapsulated and transported. I assume the same way normal audio is. So it should sound the same, but still worth a listen for fun. Of course I would need non-hdcp and hdcp content that was from the same source... hahaha.. good luck on that one i suppose..
As for the fiber transport, a single fiber is preferable. Using four fibers means they are using a separate fiber for R,G,B, and clock. Now you have the same data skew problem you have with copper cable although the fibers are much tighter in this spec so it generally works up to 1500 feet.
So you would prefer to serialize the data stream and demux it at the other end.. Hmmm... I can see how that would be good. I do like transporting packets using HD-SDI vs HDMI.. Yes I see your point here. As long as mux/demux was done well.... Hmm.... Good point... My bad... My thoughts were more about bandwidth of putting that much into one pipe - even a fiber pipe..
You know,,,, i took some of the first bulk 1694A Belden shipped long ago. Ive pulled more then I could even count and ive done it all in residential homes. It used to be my standard for 292M work in homes. But now with 3G-SDI and SMPTE 424M
here, 1694A is not good enough. Anyone doing broadcast or post work should be installing 1794A now. http://www.belden.com/pdfs/pressrel/041210pr.pdfhttp://www.belden.com/techdatas/metric/1794A.pdf
This is shipping.. Ive been through some already.
You should talk to your company and start using 1794A.
And then there's that self normalling patch jack in the path! X2! OMG! Point is the professional mastering facilities don't worry about these issues as they are not as extreme as you may think. And we make a share of the BluRay masters!
As I said earlier in this thread. HD-SDI ( 292M ) seems pretty immune to jitter effects.. I have not been able to see any differences in long or short runs of any kind of HD-SDI cables.
besides you use files to make bluray master discs not live feeds over 1694A.
But your point is well made. HD-SDI 292M is a great format very immune to about everything until you get to sparkle..
The systems I work with are better then most post houses in the burbank / hollywood area as I have spent time in them. I have 2 clients who do post work. They believe what I do, that some digital cables do matter even if you cant explain why in technical terms. It does seem its the audio digital cables. Sorry its impossible to change my mind on this subject because I have done countless direct A/B's and its always the same. There are differences that cant be explained by simple technical measurements. As a engineer and SMPTE/AES/SID member I do understand the technical aspects of cable and the signals on them. However I dont use test equipment to hear and I can actually hear differences that I cant measure. I believe there are things we just dont know how to measure that make for differences.
Also and importantly to your discussion, its reproduction where jitter matters. Post gear all reclocks, stores, buffers and normally does not deal in real time. Any jitter is resolved along the way by things like hard drive storage, tape or other things that completly remove any previous jitter effects. Its live reproduction where jitter matters.
Lets just agree to disagree on this subject and lets return to on topic discussion.
I have heard from a few people on my debate on this subject via email today and it appears I am leaning towards a active balaun solution rather then a optical one. The reason is that it appears that the optical solutions seem to be unstable and a bit buggey. BUT I have not heard from my friends at DTRO-Vision yet. So we shall see..
This is fun because I am learning things... For example...
A hdmi transmitter will put some "pre-EQ" on the signal so a source device will have a set length of cable in mind and doing a really short cable is not a good idea as then the signal is too hot by the time it reaches the receiver and cause issues. So you actually want to match up a length or EQ on a cable setup so the EQ's work out correctly and the levels are good.
I would have thought that a super short run would be the less jittery solution and the best way to go, but that turns out not to be true..
I still have a few more people to hear from on this issue.
Gefen by the way recommend a active balaun solution over a fiber solution for a 100 foot run.
You know I have not even read the HDMI 1.4 spec. I should...