In depth: H264 Decoding on Mac

[David Roth weiss]

Unfortunately, nothing there really explaining FCP’s h.264 issues.

David Roth Weiss
Director/Editor/Colorist
David Weiss Productions, Inc.
Los Angeles
https://www.drwfilms.com

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A forum host of Creative COW’s Business & Marketing and Apple Final Cut Pro forums. Formerly host of the Apple Final Cut Basics, Indie Film & Documentary, and Film History & Appreciations forums.

[Rafael Amador]

[David Roth Weiss] “Unfortunately, nothing there really explaining FCP’s h.264 issues.
“
Explains everything:
“Depending on the alignment of the stars, you may be riding one of three H.264 decoding trains. The ultrafast, low power hardware decoding MagLev, the very fast, but slightly less efficient QuickTime X TGV, or the very slow, power hungry QuickTime 7 Amtrak”.

“The hardware decoder for example is limited to a subset of H.264 files, and can’t handle some of the more sophisticated flavors. The QuickTime X software path is slightly more capable, but isn’t fully backwards compatible with all QuickTime files. The QuickTime 7 path is old reliable, the fallback when all else fails. Because Quicktime X doesn’t support much more than playback of files, most editing and compression applications are still limited to the QuickTime 7 path”.

“Final Cut Pro uses the Quicktime 7-style decoding”

rafael

http://www.nagavideo.com

[Andrew Rendell]

[David Roth Weiss] “Unfortunately, nothing there really explaining FCP’s h.264 issues.”

Well, it does kind of explain how come Quicktime is so good at playing back h.264 files.

If you look at something like this: https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC you can see where issues might arise, e.g.,
“Using previously-encoded pictures as references in a much more flexible way than in past standards, allowing up to 16 reference frames (or 32 reference fields, in the case of interlaced encoding) to be used in some cases”