MacPro Mid 2010 upgraded to 12 core 3.33GHz, Mac OS 10.12.6, MC 2018.12.7, GTX-680, 32GB Ram, USB 3 card and fibrecard to Fibrenetix JBod.
I know Avid has improved DPX performance on exports. On my usual systems an hour show went from 8-9 hour export to more like 6 ish for approx hour long 4096_2160 show.
Usually my source material is DNxHR HQX that was transcoded from Panny Varicam 35 AVC-I. The HQX source comes from the fibrenetix 16TB san chassis with 4GB fibre connection and I export to GRaid 20TB enclosures.
Yesterday I had native AVC-I source media from a GRaid USB 3.0 enclosure as a source and target was another 20TB Graid enclosure both hooked to the USB 3.0 card on the Mac Pro. The DPX export for a 51 minute show was just under 3.5 hours.
I did a Black Magic Disk speed test today on the target Graid and it was approx. 320 MB/sec, the source Graid was 215MB/sec. I checked my fibrenetix on a couple different volumes and the 16 drive raid had a pretty consistent read speed of 350 MB/sec.
I had thought I would see the source Graid disk speed be much faster than the fibrenetix but it's much slower. This only leaves the fact that I was exporting DPX from native AVC-I and not DNxHR HQX. I started transcoding to HQX when we started doing 4K because it linked and generally played nicer in Avid than the ama linked camera original media. I know in general DNxHR/HD media is easier on the cpu to playback but it would seem that exporting to DPX the processing goes significantly faster when coming from AVC-I native the HQX. Does this make sense to those with more codec/processing knowledge myself. Could the smaller data size of the AVC-I be the main faster for the faster export or is there something about how the computational/processing is done under the hood that makes export to DPX faster when the source is AVC-I. I would have thought that given HQX is less compressed the processing would be easier but that does not appear to be the case.
No problems just curious.
John Moore Barking Trout Productions Studio City, CA bigfish@pacbell.net
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