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View Full Version : 5MB/s?? Rob deJong December 27th, 2009, 01:49 PM I do not understand the specs of the 7D. After all the positive info on image quality of 7D video, I cannot beleive the bitrate of 5 MB/s in the specs on Dpreview. What does this mean? It is much lower then most camcorders. Worse image quality? Perrone Ford December 27th, 2009, 01:52 PM Umm, common mistake. The "B" is capitalized. 5MBps = 40Mbps. Usually you see the Mbps listed for camcorders. Mark Holmes December 27th, 2009, 03:39 PM Yep - it's easy to forget the bytes/bits thing... Ian G. Thompson December 27th, 2009, 05:12 PM Yup....confusing. As much as I already know this I still get caught up in the confusion every now and then. Pedanes Bol December 27th, 2009, 08:21 PM Quicktime inspector shows 48 mbits/s for the original 7D 1080/30p clips. Ian G. Thompson December 27th, 2009, 08:32 PM Yup...that 48 megabits/s equals around 5.5 MB/s. Keith Moreau December 28th, 2009, 12:20 PM Has anybody seen any codec related motion artifacts at this pretty high bitrate and theoretically good codec? I haven't noticed but I haven't been looking hard. Perrone Ford December 28th, 2009, 12:32 PM Has anybody seen any codec related motion artifacts at this pretty high bitrate and theoretically good codec? I haven't noticed but I haven't been looking hard. Many. And I've posted some here. Liam Hall December 28th, 2009, 12:43 PM Has anybody seen any codec related motion artifacts at this pretty high bitrate and theoretically good codec? I haven't noticed but I haven't been looking hard. Loads. Some shots have been totally unusable due to the failings of the codec. But at least I know what to avoid now:) Jan Tervo January 1st, 2010, 01:20 PM Loads. Some shots have been totally unusable due to the failings of the codec. But at least I know what to avoid now:) Could you send some examples, please. Kind regards, jan Barry Green January 2nd, 2010, 04:48 PM Has anybody seen any codec related motion artifacts at this pretty high bitrate and theoretically good codec? I haven't noticed but I haven't been looking hard. Understand that while the bitrate is pretty high, and the codec is theoretically good, the particular implementation of the codec is simplistic, so the overall performance isn't nearly as good as you'd expect. Not all implementations of h.264 are equivalent. There are certain features or tools that the designers can choose to use or not use. On the 5D/7D, they chose not to use B-frames, and B-frames give the codec incredible efficiency. As a net result, 50mbps of h.264 on the 5D/7D isn't nearly as robust as the 21mbps PH mode of AVCHD h.264 is. So -- to sum it up, the codec in the 7D is pretty good, but as for codec artifacting, it's probably only about HDV caliber when all is said and done. |