GH2 Hack Considerations

Apefos Adapter

Apefos Adapter

Well-known member
Some considerations about the rack:

1- Broadcast compression is much more compressed than the hacked footage, dvd output and web output does not take benefits from the hacked footage due to resolution and data rate, so the main reasons to increase data rate would be:
A- for the videomaker / filmmaker have a more pleasant experience seeing the footage?
B- for a film transfer or DCP (digital cinema) output and project in a theater?
C- BluRay output for a maximum 1 hour and 15 minutes at 5 MBps?

2- So would the iso limit hack up to 12800 be the main reason to do the rack?
 
I may be wrong, but I don't think broadcast and blueray footage are encoded with the same codec, so the bitrates don't translate.
These cameras need to encode video in real time, which is very taxing on the processor. High compression rates (like those used on blueray) take your computer a lot longer to transcode than the camera does to record.
Part of that is because the camera has optimized video encoding processing, but the other reason is because the camera is recording in a codec that is better suited for real time compression. The downside is that you don't get the same amount of quality per megabit as a more CPU-intensive multi-pass encoding.
So, I think what some folks are doing is pushing the bitrate as high as they can go in camera, that way when it gets recompressed into a different format (with a lower bitrate), it will still look good.

But between you and me, I agree that pushing the bitrate has arguable value at best. ISO hack, on the other hand, is very useful!
 
I don't think people understand why the bitrate needs to be pushed so high. I don't completly understand it myself but what i do understand is in order to get those I frames which is at GOP1 the bit rate needs to go higher. He(driftwood in this case) is not just doing it to do it. There is a reason for his method (which he can explain much better than me).
 
High bit rates offer two across the board advantages that are useful for almost any delivery format:

1- Lower noise at higher ISO settings
2- Smoother image motion

If you don't care about either of these issues, then the hack might not be for you.
 
another points to consider:

higher bitrate can give a better chromakey results

also the image tweaking like color correction / brigtness, contrast, gamma improvements can give better results in post...

kingston class 10 cards works great for 40mbps 5MBps

for higher bitrates the cards starts to became very expensive and less record time per card, also more storage space in computer
 
Even the most expensive cards are stupid cheap

You can get 30mb's Sandisks that work with the 176 patch, 16gb, or 30.00

There's NO reason not to use the patch other than spanning.
 
The codecs used in broadcast are not the same as DVD or BluRay. It's not apples to apples. To put it simply it's not just about how much total data is contained in a video file. There's also the issue of how that data was created and how much of the original you will get back when it's transduced again back into images. Long GOP is also a pain to edit. It's less of an issue than it used to be but it can wreak havoc with your editing software. And of course, when you want a file to stay high quality even when compressed you have to start with a higher quality original. No matter what CSI shows might otherwise imply.
 
I use the hack because:

1. Long-GOP motion looks bad. 1GOP or INTRA looks like film or Red. True digital cinema look.
2. With the stock GH2 recording, the shadows have terrible banding and you can't manipulate the levels at all in post.
3. All around reduction of artifacts and more organic looking grain.
 
Ian-T said:
LOL...smart alec.
Click to expand...

LOL- I used to say this over by the Canon section, when we were pushing Qscale values in Magic Lantern. Higher bitrates are of arguable value in most situations. But I do think Dishan and JMZ hit the nail on the head about codecs being different- just because blue ray and broadcast bitrates are lower doesn't mean the camera is recording at the same quality per bitrate. Sometimes a little oomf can be beneficial, but these numbers sound insane!
 
Kholi said:
There's NO reason not to use the patch other than spanning.
Click to expand...

...Apparently the new 95 MB/sec SanDisk 64 GB SDXC ( $200 at B&H Photo ) cards will span properly even when using the 176 Mbit SeaQuake patch. ( I plan on ordering a card next week to test )
 
So what seems to be the consensus on all of these hacks? I have read so many different opinions from users that I, like others I'm sure, am getting very confused.

what do most seem to go for? 46mb? 30 something? What is the best balance between stability, storage space and quality?
 
I'm more interested in knowing if there's really any difference between 95mbps and the 176mbps. It seems 100mbps is the magic number of pretty much any codec as far as size vs. quality is concerned.
 
100 is the winner then? Is this the general consensus?
What cards can write data at that speed?
 
The following settings I think are the best, it is very dificult to see difference in a fullhd monitor using higher bit rates

for class 10 card: 40.000.000 and 32.000.000 (kingston 52 usd for a 32gb card class 10)
for class 4 card: 28.000.000 and 24.000.000 (kingston 32 usd for a 32gb card class 4)
if you have a mix of class 10 and class 4 cards: 40.000.000 and 28.000.000 (and chose taking into account the card in use)

I strong recomend KINGSTON cards, they are reliable and data rate good enough for data rate above.
 
Apefos Adapter said:
The following settings I think are the best, it is very dificult to see difference in a fullhd monitor using higher bit rates

for class 10 card: 40.000.000 and 32.000.000 (kingston 52 usd for a 32gb card class 10)
for class 4 card: 28.000.000 and 24.000.000 (kingston 32 usd for a 32gb card class 4)
if you have a mix of class 10 and class 4 cards: 40.000.000 and 28.000.000 (and chose taking into account the card in use)

I strong recomend KINGSTON cards, they are reliable and data rate good enough for data rate above.
Click to expand...

What are you refering to when you write "28.000.000 ?
 
You must log in or register to reply here.
Back
Top