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HDV render in Prores : Big NO NO?
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Hey Rafael
You know I hate jump in but I think although your theory is correct, in practice, given Pelai’s system specs, he is absolutely right. An iMac has only one FW bus and there is no means to add a second. Daisy chaining a FW400 drive for render files to his FW800 media drive will only limit the FW800 transfer speeds and so be detrimental to performance as a whole rather than improve it
Just my 2 cents
Andy -
I se. The limit is the speed of the only FW bus. So the system would work faster if it would have two FW buses. Correct?
RafaelPPC G5 2x2Gh 4GbRAM/BlackMagic SD/PMBP 17″Core2Duo 4GbRAM
JVC DTV-17″/FCS2/AE CS3/COMBUSTION/SHAKE -
[rafalaos] “This is the matter. When you are rendering, you are reading and writing at the same time in the same disc. If you set your render files in a different HD from your media, the process can be faster.”
I’m sorry but this is not good advice at all. You never want your media spread out across multiple drives if this can be avoided. This leads to playback performance issue down the road.
If you want a faster process, you start with faster drives and drives that have more room. And I honestly don’t believe you’re going to see any sort of real improvement in speed using FW800 and FW400 together.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR
The new Color Training DVD now available from the Creative Cow! -
[Pelai] “My workflow was editing on an HDV timeline and on the rendering option chosing Prores.
Please let me know, maybe this is the issue all along. Maybe when rendering an HDV sequence in Prores and then exporting it, somehow recompresses once more to HDV which is why exporting has not been working out.
I am still puzzled though as to why a reference file would not work though.”My own feeling is that an iMac is just going to be very slow for this process. You’re recompressing every single file of video into a new format and a new frame size.
Remember than ProRes is full raster, not anamorphic so it’s applying a distortion to all your frames to open up the image to the full 1920×1080, not 1440×1080 which is generally what HDV is natively.
ProRes is also a much larger file size than HDV.
ProRes is good if you capture natively to it from our experience. Trying to render from one format to ProRes always adds a lot of time.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR
The new Color Training DVD now available from the Creative Cow! -
>Trying to render from one format to ProRes always adds a lot of time.
ahh, but what if the time to render to ProRes is signifcantly faster than the time to render to the native format (MPEG HD Long GOP) …. thats the crux of the biscuit here i think
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[Andy Mees] “ahh, but what if the time to render to ProRes is signifcantly faster than the time to render to the native format (MPEG HD Long GOP) …. thats the crux of the biscuit here i think”
In his case he is saying that HDV renders are very fast in a previous post. It was when he tried to render as ProRes in an HDV timeline that really slowed down the process.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR
The new Color Training DVD now available from the Creative Cow! -
i think you’d find that in practice that there is precious little if any difference in measurable performance gain when rendering to a separate hard disc regardless of whether its on the same bus or not, as the bottleneck is likely to be the actual render time not the fact that you are reading from and writing to the same drive. theoretically tho it all makes sense.
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actually its all seems a bit suss Walter
apparently there was horrendous render times reported when exporting a 32 min HDV timeline with timeline renders set to ProRes … well regardless of the timeline render setting, exporting a 32 minute HDV timeline is going to take a very long time (can we all say “conform” time?)
but when resetting the render codec to HDV then the export time was reduced to 5 minutes … for a 32 minute HDV timeline? boy, i’d like one of those Macs 🙂
which bit did I miss? there has to be something so I’m ready and willing to be corrected
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Andy and Walter,
I see I have confused you. Let me try to clarify:
What I am saying is that when editing HDV material in an HDV sequence you get the choice of changing your rendering settings to Prores within the HDV sequence (Not the same thing as having a Prores sequence)
Why you would do this is because if you render as HDV, rendering times are much longer and this option permits you to work faster.The problem arises once you have finished your editing and want to export it:
If you then have your whole timeline rendered with option to render as Prores and now try to export selfcontained or reference your exporting times go bonkers: 8hours.
Why? Because it doesn’t just export referencing renderfiles but recompressing the whole thing once again.Solution:
If you on the other hand once finished your editing delete your Prores-rederfiles and rerender your hole timeline as HDV (change your rendering option to same as sequence codec). It will take a while. But once you try to export exporting times go down to 5 for selfcontained and 2 for reference.Your second option is to change your sequence settings or drop your edited clips into a Prores sequence. Rerender again. And this time exporting times will be very short as well.
I asume by all this that the Prores-rendering option in an HDV sequence is only a meant as a temporary-while-editing solution by apple to help you work on your editing much faster than if you had to render to HDV while you were editing. It is not intended that you export a sequence from these renderfiles and therefore problems arise when you try.
One more thing that makes me wonder what kind of Prores codec the rendering option in a HDV sequence gives you is that if you try to put an HDV Prores-rendered clip (from HDV sequence) into a Prores sequence. FCP will automatically tell you it needs rendering weather the sequence is Prores 422 or Prores HQ, 8bit or 10 bit.
Hope it’s a bit clearer now.
iMac 24″ 2.8 extreme, 3gb RAM, 500 gb internal disk + 500 gb FW800 external drive.
OSX 10.4.11, FCP 6.02, QT 7.3 -
Rafael,
No hard feelings I hope.
I understand now what your suggestion is by separating renderfiles and media on two separate drives. But here I must agree with Walter, I have never had that kind of advice rather the opposite, to always keep them together if you can.And as Andy said it is the one FW bus that decides the speeds, if I were to, for some reason put a FW400 disk together with my FW800 disk the transfer speeds of the FW800 would drop to FW400.
iMac 24″ 2.8 extreme, 3gb RAM, 500 gb internal disk + 500 gb FW800 external drive.
OSX 10.4.11, FCP 6.02, QT 7.3
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