AVCHD,AVC-Intra, vs MXF HELP !!

[Michael Ferreira]

Hey Guys, Not sure if this is the right place to post this so if it's not sorry. Any help on this subject would go a long way for me.

I have been looking to get a new camera and I feel as if I have out grown the AVCHD Codec. What I mean by that is I feel like at the end of the day no matter what type of glass we put on the camera(VG20 for example) and keeping our gain at 0. we are still going to have noise due to the avchd compression.

I almost pulled the trigger on the FS100 but the AVCHD codec with the 24mbps cap bugs me. I then looked at breaking the bank with the Panny HPX250 with AVC-Intra 100mbps but after looking at some RAW footage off the camera i noticed lots of noise not sure if it was codec or something else. The guy that tested the camera said his gain was at 0. I'm scared to risk the ass kicking from my wife on another AVC formated camera that might still have the compression artifacts.

I have read great things about the XF100/105 from canon and the 50mbps codec with 4:2:2 and the camera seems to be at a decent price point but it just looks a little small and toyish, IMO.

I guess what I'm looking for is a codec with the least compression and even though AVC intra 100mbps is higher the the MXF I'm thinking it has a higher compression still and that will cause the noise and artifacts.

If your still reading this long post thanks for sticking with me, we are moving away from web videos and producing content that many people will see. So I guess i'm second guessing myself. Any help really would be appreciated.

~mike

[Al Bergstein]

What do you want to shoot with it? I've shot good stuff with both avchd and mxf. Gain isn't an issue, it's to be understood.

[Michael Ferreira]

Hey Al,
We can shoot anything from someone doing yoga in the park to an indoor event. it's just now that we are slowly stepping away from web videos and producing content for larger mediums I feel as if the AVC codec is going to limit us or create undesired footage.

It's not the gain I'm worried about I understand gain and how to control the camera to get the footage needed my worry is the compression of the codec. I think Canon's MXF 50MBPS 4:2:2 is a very good starting point but have not had the pleasure of working with raw footage that was very good.

[Predrag Vasic]

First off, MXF is just the container definition. In case of Canon, it uses MPEG-2 to compress the video, however, unlike HDV (which has 4:2:0 chroma subsampling), Canon does it at 4:2:2 resolution. So, it is a combination that is likely to give better results than AVCHD at 24Mbps. While MPEG-2 is generally about half as efficient as H.264 (codec within AVCHD), implying pretty much same image quality as MPEG-2 at 48Mbps, the additional chroma sub-sampling should make the resulting image slightly better, at the expense of twice the required storage for a comparable AVCHD (H.264) file.

As far as noise and compression artifacts are concerned, the codec itself does NOT induce any by definition. Any resulting noise may come from various other sources: lens, image sensor, digital image processor, excessive motion (where compressed video tends to break apart, regardless of codec)...

I am not a big fan of the AVCHD format (needlessly complex wrapper for our purposes), but am a big fan of AVC (H.264) codec. It is an extremely efficient, modern compression solution with enormous potential; certainly significantly more capable and superior to the (already 20 year old) MPEG-2. Hardware is slowing catching up to it and I'm sure, in a year or two, it will be handled as easily as HDV (MPEG-2) was handled by hardware of 5 years ago.

[Dan Asseff]

Predrag,

I could be wrong but AVCHD and (H.264) codec are the same codec. I have the Sony FS 100 and it is the most beautiful footage you will get for a camera at that price point.The super 35 censor allows shooting in low light at a very high gain with very low noise. I have read were someone would use an external recorder to compare the images and didn't notice very little differences.

Michael,
Don't get caught up in codec debate, the codec is a very good codec. Here is a wedding i did with the FS 100 and a NX5. Forever Moments Video Productions There is noise in the NX5 but not in the FS 100 and they have the same exact codec.

Dan

[David Heath]

Originally Posted by Dan Asseff

I could be wrong but AVCHD and (H.264) codec are the same codec.

You're half right - AVC-HD is a subset of H264. So whereas a baguette is bread, bread is not necessarily a baguette.....! :-) Likewise, AVC-HD is H264, H264 is not neccessarily AVC-HD.

Originally Posted by Predrag Vasic

While MPEG-2 is generally about half as efficient as H.264 (codec within AVCHD), implying pretty much same image quality as MPEG-2 at 48Mbps, ........

Not quite - the "MPEG2 requiring twice the bitrate of H264" (all else equal) comment is an approximation that only really applies at lower bitrates, typically those for HD broadcast transmission. Hence why HD broadacast typically may need about 19Mbs if MPEG2 is used, but something just under 10Mbs with H264 for equivalent quality.

Increase the bitrates, and the comparison doesn't scale up in the same ratio. At more than 10Mbs or so for AVC-HD you don't get twice the efficiency of MPEG2. The higher the bitrate, the more true that becomes.

Likewise, the 24Mbs figure you quote for AVC-HD is a max figure, the average is 21Mbs or less which is a better figure to use for comparison.

As well as the theoretical advantage not being twice at these bitrates (which would imply 42Mbs equivalent with MPEG2) then a lot also depends on the individual coder. Spend thousands on a broadcast coder (or tens of thousands?) and yes, you'll get the 2x efficiency at 10Mbs figures. Talk about a chip in a prosumer camera, the lot costing vastly less than the broadcast coder, and it won't be as good by a long way - hardly surprisingly. Exactly how much is difficult to say (impossible, really, it will vary from model to model, and vary subject to subject) and I wouldn't say much other than on a prosumer camera I'd expect 21Mbs AVC-HD (24Mbs peak) to sit somewhere between HDV (whilst also giving full raster 1920x1080) and 35Mbs XDCAM-EX.

[Kenneth Maultsby]

Originally Posted by Al Bergstein

What do you want to shoot with it? I've shot good stuff with both avchd and mxf. Gain isn't an issue, it's to be understood.

Al
How is PPro 5.5 on AVCHD? I have PPro 5.0 but when I use the J K L keys sometimes I get a delay mostly when I use the J key for reverse and sometimes forward. Sony mt2s. I also use Media Composer 6.0 now I and transcode it and I do not get the same problem. My system i7 930 overclock to 3.4 MHz Nvidia 470X CUNA activate. To keep it simple MC is more responsive than Premiere.

[Richard Davidson]

Dan, in trying to learn more about filming can you give me an example in that video where the "noise" is so I can see what you are looking at.

Thanks

[Dan Asseff]

Richard,
At 5:29 and 6:03 were shots with the NX5 and I think the rest where with the FS-100. The point is that they use the same codec and the FS-100 blow the NX5 away in low light. Also make sure you watch it in HD because I couldn't tell that much different in SD.

Dan

[Richard Davidson]

In those shots it looks like the blacks are more washed out than the other shots. I don't know how to describe the shot at 5:29 other than being more mottled. Is this what you are talking about as far as noise? The shot at 5:29 looked much worse than the one in 6:03 so what am I missing there?

Thanks