Canon WP-V1 Housing!

[Gombessa]

Huh, so if I understand correctly, the point of HDMI capture is to save time post-transfer (either from working with AVCHD or converting to another format) by leveraging real-time hardware decoding from the camcorder. What you are relying on is the accuracy of the hardware decoder versus the software codec you would otherwise use on the PC.

 

[ronscuba]

Read this, then come back to the table for further discussion.

http://69.15.88.17/hdmisipics/HDMI_in_HDV_and_AVCHD_Camcorders.pdf

Then you too, will understand what it means.

I thought the camcorder recorded compressed HDV or ACVHD to the camcorder. I was under the impression that HDMI capture meant recording live to a PC or remote hard drive uncompressed with an HDMI cable.

Maybe I am mistaken. Are you saying you can extract uncompressed video from the compressed video recorded to the camcorder ? Or that it will look as good as hardwired uncompressed live HDMI capture ?

 

[Gombessa]

Maybe I am mistaken. Are you saying you can extract uncompressed video from the compressed video recorded to the camcorder ? Or that it will look as good as hardwired uncompressed live HDMI capture ?

That's not what the PDF image claims. Instead, lossy compression (AVCHD) is merely decoded for playback through HDMI, and the "pseudo-raw" output captured directly as if it were true raw. The format is changed, but the compression has already taken place, so you're not getting back anything that was lost. The quality itself should be no better (and likely will be somewhat worse, if it's like typical embedded hardware decoding that runs in real-time priority) than a slower, non-realtime decode through software. The only real benefit I can see is that you save time manually converting from AVCHD if you don't want to work in that format.

Conch, does that sound right?

 

[ronscuba]

That's not what the PDF image claims. Instead, lossy compression (AVCHD) is merely decoded for playback through HDMI, and the "pseudo-raw" output captured directly as if it were true raw. The format is changed, but the compression has already taken place, so you're not getting back anything that was lost. The quality itself should be no better (and likely will be somewhat worse, if it's like typical embedded hardware decoding that runs in real-time priority) than a slower, non-realtime decode through software. The only real benefit I can see is that you save time manually converting from AVCHD if you don't want to work in that format.

Conch, does that sound right?

That's what it looks like to me too. Kind of similar to what $100 cineform neoscene software does. Converts the compressed video files to uncompressed for easier editing and better color correction/editing. But does not improve on the quality of the already compressed video files.

The Black Magic Intesity card does do hardwired live uncompressed capture. But I did not see on their website where they say it can convert video from compressed to look as good as uncompressed.

I still have to read through the 11 page linked article to see if it says anything different. To me, HDMI capture means live uncompressed during recording. Conversion of the already compressed video files through the HDMI port is something different in my mind. Goal is to get the best video quality possible.

Don't want to argue. Being right or wrong is not important. Let's just get hard facts out there so we can all make decisions on how to get and make the best videos possible.

 

[Conchchowder]

That's not what the PDF image claims. Instead, lossy compression (AVCHD) is merely decoded for playback through HDMI, and the "pseudo-raw" output captured directly as if it were true raw. The format is changed, but the compression has already taken place, so you're not getting back anything that was lost. The quality itself should be no better (and likely will be somewhat worse, if it's like typical embedded hardware decoding that runs in real-time priority) than a slower, non-realtime decode through software. The only real benefit I can see is that you save time manually converting from AVCHD if you don't want to work in that format.

Conch, does that sound right?

What HDMI 1.3 Can Do, Can't Do, and Possibly Won't Do [Text View] - AVS Forum

What everyone is missing is the fact that there is HDMI coding going on in the transport stream into the SDHC card...just as the 24p and 30p signals are incoded in a 60i container (extracted via programs such as Voltaic HD), the benefits of HDMI transport are not lost. The bandwith of HDMI allows for more information (decoded and sent via the HDMI 3.1 signal. It is the very use of the HDMI standard which enables the signal to be so much better than just popping out the chip and sticking it in your laptop.

I asked Henry Olonga, over at Vimeo, to do a comparison using his Blackmagic card and the raw signal going into it and then dumping the recorded SDHC program through the very same workflow to see if he notices a difference.

Mind you that I'm using 32GB Sandisk Extreme with 30MBs transfer rate.

http://gizmodo.com/5301931/sandisk-claims-title-of-worlds-fastest-32gb-sdhc-card

This is essentially raw video quality...but it is too much for most transfer systems, thus necessitating HDMI transfer into the Blackmagic (or similar) PCI Express input of a PC or the use of an adapter to use with a laptop such as this one PE2L (yeah...hook up a Radeon or nVidia card to your laptop with external power with this bad boy).
If nothing less, this gives you HDMI input to your laptop.

 

[Gombessa]

Thanks for the link Conch, I'll read up about this over the weekend, fascinating stuff (I stopped following A/V after DVI).

But from that link, ""Billions" of colors is more than the eye can see"? Ugh, blasphemy. I've seen native 10- and 12-bit output and nothing could be further from the truth. The very next sentence regarding visible color banding in the 8-bit domain debunks that. You may not easily notice without direct comparisons, but that trope is as tired as "the human eye can only see 30fps"

 

[ronscuba]

What HDMI 1.3 Can Do, Can't Do, and Possibly Won't Do [Text View] - AVS Forum

What everyone is missing is the fact that there is HDMI coding going on in the transport stream into the SDHC card...just as the 24p and 30p signals are incoded in a 60i container (extracted via programs such as Voltaic HD), the benefits of HDMI transport are not lost. The bandwith of HDMI allows for more information (decoded and sent via the HDMI 3.1 signal. It is the very use of the HDMI standard which enables the signal to be so much better than just popping out the chip and sticking it in your laptop.

I asked Henry Olonga, over at Vimeo, to do a comparison using his Blackmagic card and the raw signal going into it and then dumping the recorded SDHC program through the very same workflow to see if he notices a difference.

Interested to hear and see the results of his test. I think I will head over to DVinfo.net forums, to read up on the Blackmagic card. That board always has very knowledgeable members posting and testing equipment, software, etc..

Conch, I guess the key question is are their visual advantages to bringing previously recorded compressed video from the camcorder to the pc via HDMI over more traditional methods of tape and file transfers ??

Maybe one of the other scubaboard members with pro level experience will chime in. I think Perroneford and Billy work or have worked in the industry.

 

[Conchchowder]

The Black Magic Intesity card does do hardwired live uncompressed capture. But I did not see on their website where they say it can convert video from compressed to look as good as uncompressed.

If you look at the flowchart from the HDMI whitepaper, it shows that the video coming out of the error correcting/ scaler is uncompressed video.

Read this.

Filmmaker Magazine | Fall 2006: HDMI: UNCOMPRESSED HD FOR A SONG

especially this part.

"In other words, the HDMI signal coming from Sony’s latest inexpensive single-CMOS consumer camcorders, whether HDR-SR1 or HDR-UX1, contains full-blown 1920 x 1080 uncompressed HD and multitrack audio, because that’s what these little guys handle internally in their digital signal processing (DSP) circuitry. That’s what the new logo “Full HD 1080” means. Who says we don’t live in an age of miracles? (What’s more, in the case of the HDR-SR1 and HDR-UX1, audio is Dolby Digital 5.1 Surround!) "
(This includes the HF20/200)

...and this thread

AVCHD is lossy? - DVXuser.com -- The online community for filmmaking

"Customers recording to HDV tape (read SDHC) also benefit from HDMI uncompressed capture and editing. Once the HDV footage is recorded uncompressed via HDMI, and graphics and effects are placed, the edited video will retain full HD resolution and color depth. This high quality editing can be viewed in real time via the Intensity HDMI video output on large screen televisions or video projectors. Because Intensity's media files are fully compatible with Blackmagic Design's DeckLink and Multibridge capture cards, users can even play-out to broadcast tape decks by moving content to a DeckLink or Multibridge based system. " (from Blackmagic press release page)

Goal is to get the best video quality possible...Don't want to argue. Being right or wrong is not important. Let's just get hard facts out there so we can all make decisions on how to get and make the best videos possible.

Exactly.

Henry doesn't log on frequently, so it may be a bit before he answers.

 

[ronscuba]

Hi Conch, I think where we are crossing theories is if the HDMI capture is done live never compressed vs. already recorded onto the camcorder then captured to the pc with HDMI.

I agree, live never compressed live HDMI capture is the best. I just have not read where once the video is already recorded compressed onto the camcorder, it can be brought back to never compressed visual quality using HDMI. Maybe I am reading or interpreting the articles incorrectly.

We can wait for Henry to answer or conduct his tests. Meanwhile I found some interesting reviews by magazines and posts over on DVinfo.net. Who is to say these people are any more or less knowledgeable than us, but interesting reading none the less.

Capture Card Review : Blackmagic Design Intensity HDMI Capture Card

http://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/129637-firewire-hdmi-capture.html

http://www.dvinfo.net/forum/general-hd-720-1080-acquisition/126916-usb2-vs-firewire-vs-hdmi.html

http://www.dvinfo.net/forum/sony-hv...ape-play-back-using-hdmi-versus-firewire.html

Best way to go on HDMI capture - The Digital Video Information Network

 

[Conchchowder]

Hi Conch, I think where we are crossing theories is if the HDMI capture is done live never compressed vs. already recorded onto the camcorder then captured to the pc with HDMI.

I agree, live never compressed live HDMI capture is the best. I just have not read where once the video is already recorded compressed onto the camcorder, it can be brought back to never compressed visual quality using HDMI. Maybe I am reading or interpreting the articles incorrectly.

We can wait for Henry to answer or conduct his tests. Meanwhile I found some interesting reviews by magazines and posts over on DVinfo.net. Who is to say these people are any more or less knowledgeable than us, but interesting reading none the less.

Capture Card Review : Blackmagic Design Intensity HDMI Capture Card

Firewire or HDMI capture ? - The Digital Video Information Network

USB2 vs. Firewire vs. HDMI - The Digital Video Information Network

capture from tape play back using HDMI versus firewire... - The Digital Video Information Network

Best way to go on HDMI capture - The Digital Video Information Network

Every article written is from at least a year ago. The HF20/200 was released in Feb of this year. The new Blackmagic Intensity, used with the HF200, will make use of the new features of the Canon...but with one caveat. Canon has no Firewire and thus, no timecode can be transmitted...but this doesn't detract by the improvement of using HDMI to output a superior signal (still inferior to those of $5000 cameras) but it is my contention that sending a signal, through HDMI is superior due to internal decoding, error correction, and scaling (you would have to drop a couple of thousand to purchase an external video processor for decoding, scaling and error correction) and then inputting to the Blackmagic than dumping 480 Mb/s USB video or popping out the chip. I'm merely saying that the quality, due to higher bandwith and decoding of HDMI features...uncompressed...is different now than it was years ago. There have been improvements made in the workflow, codecs (AVCHD wasn't mentioned a few years ago and even that has changed)
To compare workflow of even a year ago, to workflow today is comparing apples to oranges.
When I worked in television, we were stuck with dinosaurs such as the TK-76...the standard for ENG crews in the early 80's...the Beta killed these cams...then came 1" Quad recorders...now tapeless, NLE's (eliminating the need for sync tracks and LE) and the ability to shoot video which surpasses all of the dreams we have ever had as far as prosumer users.
What we need is input from current engineers, using our camera (the HF20/200), and devices for inputting HDMI signals into our workflow. This includes clarification of transfer of files vs images (the loss of 24/30p editing flags when drag and dropping files from the SGHC) and the use of programs such as Voltaic HD.
We need to pay attention to the dates on forums when we bring them to the table. The info we need is time-sensitive and should be the most current available. The HDMI whitepaper IS from 2006 but shows flow going uncompressed.
At the quality which we have now, as opposed to 2006...and even last year, I think this is important.