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Re: What DNxHD setting for my Canon 5D footage conversion?

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Mark Spano
Re: What DNxHD setting for my Canon 5D footage conversion?
on Jun 9, 2014 at 9:10:42 pm

This is not necessarily true. You have to think deeper about what is going on with each of these formats. A temporal compression codec like H.264 in 5D files means that you can achieve a bit higher quality recording using lower bit rates. It is not always encoding a full frame for every shot frame, cheating with temporal compression. This is similar to how high quality is achieved on Blu-ray using only 30-40 Mbps (VBR). In the world of intraframe compression codecs like ProRes or DNxHD, these are encoding a full picture for every frame. They are not temporally cheating, so you need a higher bit rate to accomplish the same trickery that H.264 accomplishes with less. So I usually do the math like this: any H.264 bits x 4 ≈ equivalent quality bits in ProRes/DNxHD. So your 20-30 Mbps H.264 from your 5D should really be transcoded to around 80-120 Mbps ProRes/DNxHD to retain max quality. That is equivalent to DNxHD 115/120 or ProRes LT/422. This is just my experience but I have definitely noticed some loss if going to ProRes Proxy or DNxHD 36/45. Both of these have "more bits" than the H.264, but they're not necessarily the same type of bits.

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