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In particular the multi-generation images will take a bit longer.

Two previous quality analyses have been published for CineForm codecs - one for our 8-bit codec used in Aspect HD and Connect HD , and a second for our 10-bit codec within used in Prospect HD.  Both previous analyses were performed using Premiere Pro as the host application.  The previous HDV codec analysis used a much older version (v1.2) of the CineForm codec.  Since that time many visual quality enhancements have been added, so it became time to perform an updated 8-bit codec quality analysis. 

In this test we used Sony Vegas 6.0c instead of Premiere Pro, and we used the latest version (v2.3) of the CineForm 8-bit codec.  (NOTE: The CineForm codec version number does not correlate with version release numbers for either Connect HD or Aspect HD).  The posted results of this test are more interactive than our previous examples by allowing you click between the source image and each of the output generations. Observing the image being "flipped" in this way is truly the best way to view the differences between otherwise very similar images -- a single-by-side comparison is less effective.

Source Image

The source image is an I-frame extracted from an MPEG2-TS stream captured by
the Sony FX1/Z1.

Click each of the check boxes to see the generation loss of native MPEG versus CineForm Intermediate

Original M2T file
1st Generation CineForm AVI
10th Generation M2T ("native" editing)
10th Generation CineForm Intermediate AVI

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Quality Results

In the images below, key details of the image are highlighted to show many of the characteristics you may have seen in the images above. The differences between the original M2T and the first generation CineForm compression is not visible, other than in areas that benefit, even in the first generation, because of proper interpolation performed as we convert MPEG's 4:2:0 chroma to the 4:2:2 chroma space used by CineForm Intermediate.  For many production needs the quality of CineForm Intermediate is actually higher in its first generation than the source material, even if you intend to export back to HDV 4:2:0.  Properly performing this 4:2:0 to 4:2:2 chroma up-conversion is an important step for any material intended for resizing, or if it is exported to any high-resolution chroma format such as broadcast equipment or film-out projects.  This 4:2:0 error is even more apparent for deeply saturated reds and blues.  After ten generations of compression by both codecs, it is clear that only one of these codecs is designed to hold up to the rigors of post-production. 

MPEG2 is a excellent delivery format and - as proven by HDV - is also a remarkable acquisition format, but post production has new demands that benefit from an intermediate format intended for multi-generation use.  There is no quality disadvantage to using CineForm Intermediate, even for the case of a cuts-only edit that is going back to HDV -- using CineForm Intermediate will enhance your production through editing speed, application compatibility, and image quality.

Original plus Multi-Generation Images - including mark-up for clarity

Click each of the check boxes to see the generation loss of native MPEG versus CineForm Intermediate
Original M2T file
1st Generation CineForm Intermediate AVI
10th Generation M2T ("native" editing)
10th Generation CineForm Intermediate AVI

NOTE for IE Users: IE users MUST allow "active content" to view these images.  This is enabled in the top browser bar of IE.  Don't worry, nothing is being installed on your computer, but IE's security mechanism restricts active content from being displayed without your explicit permission.

Testing Methodology

These test are easy to conduct yourself.  The only tools used are Sony Vegas 6.0c plus the new Connect HD 2.0 (available from CineForm's website) that includes codec version 2.3.  The original M2T file was captured without any processing via HDLink (HDLink is the capture and conversion tool within Connect HD).  This M2T was then converted into CineForm Intermediate (AVI file) using HDLink at the medium quality setting with interlaced encoding (to match the source).  Then all multi-generation tests for both the M2T and AVI files where performed in Vegas 6.0c. 

Rendering into either CineForm Intermediate or an M2T file without applying any changes to the image is not a good test because smart rendering will kick in for CineForm (producing zero less between generations 2 and on), and MPEG will have only minor losses if the frames are not moved in time -- i.e. if the 'I' frames still line up.  (NOTE: there is less than a 10% chance that I-frames will continue to align when cuts are made in normal editing).  In our test case, the "change" applied to each image in each generation was a simple shift of the image by one pixel horizontally to the right and vertically downwards.  (This test was suggested by one of Avid's codec experts as one of their preferred stress tests for evaluating codec performance -- thanks Avid.) 

To simplify this operation I used a 3x3 convolution kernel with the top-left coefficient set to 1.0 and everywhere else to zero, and placed this filter in the output render.  The original M2T was placed on the timeline to export out through the convolution filter as gen2.m2t.  Then the new gen2.m2t file was place on the timeline and exported out as gen3.m2t and so on.  The same procedure was performed with the CineForm AVI file generated from HDLink: original.avi was placed on the timeline and exported through the convolution filter as an intermediate AVI as gen2.avi, then repeated with the gen2.avi to produce gen3.avi, etc. The final clips gen10.m2t and gen10.avi where exported as uncompressed AVIs for comparison and posting on this web page.

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