I have created a single photoshop file with multiple layers each containing some of my codec test results. Layers include, Uncompressed DPX, Samurai ProRes, ProRes HQ and DNxHD 185 encodes from the DPX and F3 Internal Mpeg 2 @ 35Mb/s. By zooming in and turning layers on and off in Photoshop you can quickly see the differences in the quality. One thing this highlighted was some duplicated pixels in the DPX files from the Gemini. This issue has now been fixed.
[downloads_box title=”PhotoShop Codec Layers”]
Download the file here
4 thoughts on “Codec and Recorder Tests: Layered Photoshop File”
Thank you very instresting.
Nice idea to include the alpha channel in the mix Alister. I was able to put all the shots on a FCP timeline as single frames and put the alpha above them, then arrow back and forth one click at a time to see the differences.
You are obviously right about ProRes noise- and the DnX does look remarkably clean (but not quite as much as) the Gemini uncompressed. Since ProRes and DnX are both mathematically lossless codecs I’m a bit stumped to understand why they differ in quality but I guess that’s best answered by the codec designers.
Have you tried out the Blackmagic Shuttle? Just curious as to how a $400 uncompressed recorder stacks up against the Gemini.
ProRes is not mathematically lossless, nor is DNxHD. These are definitely lossy codecs, However Apple and Avid describe them as “Visually Lossless” which implies that you won’t see any loss of picture information during normal viewing.
Not tried the shuttle. I’ve heard quite a few stories that have put me off.
Thanks Alister. This is a great way to see the differences that you have described.