The Canon 5DMK2 is making big news in the Film and TV world. The example video by Vincent Laforet looks quite amazing as a web file. But to fully assess the quality of the images we need to examine the raw files coming from the camera. Canon made these files available on their website but has since removed them due to high demand (bandwidth costs?).
Firstly, let’s discuss what format the 5DMK2 uses for recording its video files. It is a H.264 codec with audio giving a 40mbit stream in a standard MP4 container. The H.264 profile is highly compatible with Quicktime and as such can be imported into Final Cut Pro or Premiere on Mac and PC without too much fuss. This is great news but there are issues one should be aware of.
The profile used can only compress at 4:2:0 colour space. This isn’t great, especially if you want to do any intensive colour correction. It is also likely that the encoder is not using some of the more advanced encoding features available in H.264, especially as it is a real-time encoder.
H.264 has a lot of potential, however this implementation is far from pristine. I will use a comparison to better explain this dilemma. Software encoded Quicktime movie trailers such as those posted on apple.com (a very similar file type) have an average bitrate of 9mbit but in my opinion, are producing far superior images than the 5D is at 36.5mbit (the video portion of 40mbit). One would expect a significant increase in quality when comparing the 5DMK2 with Quicktime trailers given the math of 36.5 over 9. However, this does not appear to be the case. I am not that surprised as I haven’t seen any real-time H.264 encoders that hold up very well. I expect that over time, the quality achievable for H.264 real-time encoders will improve to near software (non real-time) encoders. Just look at the evolution of the DV and HDV codecs for a sign of things to come.
That said, the quality of the 5DMK2 raw files are disappointing when considered in the light of serious colour correction. Macro-blocking (visible square areas) are evident in the dark regions of the video. All said, 5D still does deserve a lot of attention. The codec performance may be letting it down at the moment, but that could change. The real issue here is that we have a 35mm sensor in $3500 camera body that can take common hi-quality lenses. Getting the image of the sensor in a quality that a film maker wants will happen sooner or later.
To help with examining these raw files, I have both cropped a sequence and isolated an image to demonstrate some of the observed issues with the raw files produced by the 5D..
The above SWF file shows a section of the sky from the “bridge shot”. I have extracted frames from this shot, converted them to uncompressed PNG and placed them in a SWF file. You’re looking at the raw, uncompressed footage playing back in the Flash window. Total of 25 frames. Note the noise and visible macro blocks.
5D example
I took the above section from a frame of a predominantly bright image. As to be expected, a well lit image looks clean and devoid of “blocking”. But on closer inspection we can see something passing in front of the lens creating the darker to lighter gradient. As you can easily see, noticeable “blocks” are evident, especially in the blue portion.
What is the ASA that he shot the entire thing at? 1600 ? That may that have something to do with the quality? I know it does in my camera shooting stills, and the higher the ASA, the more noise, the less good the compression can be.
Hi Onno,
I understand where your comment is coming from, however, this is why I have the mostly very well lit image with the white,blue,black gradient. The ASA you have been well down in that shot, but we still see compression issues. This indicates that in general, the compression algorithm used simply is not doing a very good job generally. Higher ASA and the introduction of sensor noise is simply going to make this problem worse.
Still working out how to play back the files without skipping. The original files skip severely. Its not hardware as its a a relatively powerful mac that can play 10bit and hD files. I am using FCP 6.0.5 which also should play this codec with no problems. But here too, it skips. When I export it out as a HD file, it plays back smoothly.
Hi Ben,
What can I say, they work fine on my Intel Mac. If you are having problems, convert them into your desired timeline codec and edit from them. Ie ProRes possibly.
As they are H.264, don;t expect them to play well on the time line. Quicktime/FCP is not setup to play well with a H.264 based time line. Long GOP etc issues.
Hopefully in the future, native H.264 editing will become available with more efficient codec to make it all work smoothly. For now, transcoding is your friend for editing, and you enemy for disk space.
4 responses so far ↓
1 onno // Oct 24, 2008 at 7:24 am
What is the ASA that he shot the entire thing at? 1600 ? That may that have something to do with the quality? I know it does in my camera shooting stills, and the higher the ASA, the more noise, the less good the compression can be.
2 JamieG // Oct 24, 2008 at 9:55 am
Hi Onno,
I understand where your comment is coming from, however, this is why I have the mostly very well lit image with the white,blue,black gradient. The ASA you have been well down in that shot, but we still see compression issues. This indicates that in general, the compression algorithm used simply is not doing a very good job generally. Higher ASA and the introduction of sensor noise is simply going to make this problem worse.
3 Ben // Dec 4, 2008 at 6:43 pm
Hello there.
Wonder if you can help.
Still working out how to play back the files without skipping. The original files skip severely. Its not hardware as its a a relatively powerful mac that can play 10bit and hD files. I am using FCP 6.0.5 which also should play this codec with no problems. But here too, it skips. When I export it out as a HD file, it plays back smoothly.
Thanks
Ben
4 JamieG // Dec 4, 2008 at 10:24 pm
Hi Ben,
What can I say, they work fine on my Intel Mac. If you are having problems, convert them into your desired timeline codec and edit from them. Ie ProRes possibly.
As they are H.264, don;t expect them to play well on the time line. Quicktime/FCP is not setup to play well with a H.264 based time line. Long GOP etc issues.
Hopefully in the future, native H.264 editing will become available with more efficient codec to make it all work smoothly. For now, transcoding is your friend for editing, and you enemy for disk space.
James
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