DNxHD Encoding with FFmpeg

[MaeWanto]

FFmpeg is now providing Avid DNxHD (SMPTE VC-3) encoding and decoding features:
http://www.fullres.blogspot.com/2007...th-ffmpeg.html

In conjunction with Ingex ( http://ingex.sourceforge.net ), such essence can be wrapped into MXF file format and directly ingested into Avid's NLEs without any rendering process.

[Mug Funky]

hey, that's pretty cool.

i wonder if that ingex system could work like a virtual vtr? it'd be cool to be able to play out from an Ursa directly into MXF files and save myself some double-handling with tapes.

[MaeWanto]

I guess it could ... I saw a demonstration at IBC 2006 where BBC R&D was showing Ingex' features ( based on a DVS I/O board ). More info on their workflow :
http://www.bbc.co.uk/rd/pubs/whp/whp...les/WHP133.pdf
http://www.bbc.co.uk/rd/pubs/whp/whp...les/WHP141.pdf
http://www.bbc.co.uk/rd/pubs/whp/whp...les/WHP155.pdf

[Blue_MiSfit]

Very nice. DNXHD is a hell of a format, and the more supported by libavcodec the better!

If only this had been around about a year and a half ago when I was responsible for managing an uncompressed HD workflow for a feature film! AviSynth helped a lot, but this would have been super cool.

~MiSfit

[CruNcher]

Very nice. DNXHD is a hell of a format, and the more supported by libavcodec the better!

So it's better then AVC Intra @ the same bitrate ?
im building on such a AVC intermediate workflow (10 Generations) currently as my tests with Cineform and Canopus HQ where destructing both but i didn't test DNXHD yet

PS: My tests where done in the 80 mbit range reaching 51 dB for 1440x1080 30p (tough with compresed Mpeg-2 source)
Results= http://cruncher.mufflastig.com/hdtv/hdv/intermediate/

[kolak]

Originally Posted by CruNcher

So it's better then AVC Intra @ the same bitrate ?
im building on such a AVC intermediate workflow (10 Generations) currently as my tests with Cineform and Canopus HQ where destructing both but i didn't test DNXHD yet

PS: My tests where done in the 80 mbit range reaching 51 dB for 1440x1080 30p (tough with compresed Mpeg-2 source)
Results= http://cruncher.mufflastig.com/hdtv/hdv/intermediate/

Did you use highiest HQ settings or the one which gives about 100Mbit bitrate?
If you have your results up to 4 digits than you should have xx.3450 not xx.345 - heheheehe

Hmmm....Canopus HQ is great codec- extreamly fast and quality is also very good. Cineform is better (depends on quality settings), but slower. I'm supprised (or maybe not), that AVC-I is so good, but of course not as fast as 2 others.
AVC-I in Edius works briliantly- RT playback with no problems even with few tracks. Very fast encoding also (2x faster than RT for 1920x1080 60i, with 95% on 8 cores machine)- Edius is one of the best multithreaded application I've seen.

DNxHD is not going to be better than Cineform at the same bitrate, maybe slightly better than Canopus HQ, but way slower on Windows.

Andrew

[chaynik]

Any advancements in bringing ProRes support to FFMPEG? It's been 2 years

[Storyteller]

Originally Posted by chaynik

Any advancements in bringing ProRes support to FFMPEG? It's been 2 years

+1 For this question. Any news?

[RunningSkittle]

Originally Posted by kolak

...AVC-I in Edius works briliantly- RT playback with no problems even with few tracks. Very fast encoding also (2x faster than RT for 1920x1080 60i, with 95% on 8 cores machine)- Edius is one of the best multithreaded application I've seen...

x264 can achieve ~2x realtime with 1080p50 on a q6600 ~100fps thats only 4 cores

[kolak]

Originally Posted by RunningSkittle

x264 can achieve ~2x realtime with 1080p50 on a q6600 ~100fps thats only 4 cores

These are 2 different porducts- h264 is not even a product- just a "core".
Did you test I frames only at 100Mbit?

[Blue_MiSfit]

What about speed? I was under the impression that DNxHD and Apple ProRes422 were both real-time on reasonably fast systems. I can't see HD resolution AVC being real-time.

~Misfit

[Inventive Software]

Bear in mind though that they're post-production codecs, designed to be IIRC a master transfer. 10-bit is especially useful for studios because it keeps more detail. Speed doesn't necessarily matter, quality does. That said, if it's fast, it'll find its uses.

EDIT: Apple's ProRes codec is likely to be fast on Macs, but slow elsewhere.

[Mug Funky]

speed matters! it's probably second only to quality (if you're offline editing you'll want speed OVER quality).

the big deal with DNxHD and ProRes is they're heavily parallelised, and give enough compression to carry HD in the same bandwidth as uncompressed SD. meaning the hard disk bottleneck is offloaded onto the (increasingly multicore) CPU.

it means you can use cheaper hard disks to do the same tasks, and the compression is similar (possibly better than) to mastering tape formats.

...unfortunately people haven't quite got into these codecs yet, so i still have to wait forever to copy uncompressed stuff onto 1394 hard disks, tying up edit suite time and meaning lots of double-handling (ie, you can't capture uncompressed reliably over 1394, so you have to capture once then copy).

i'd love to see prores implemented into ffmpeg

[easy2Bcheesy]

I'd like to use this to transcode my 720p/60 CineForm AVIs into Avid-compliant streams, but it looks as though this implementation is for 1080i/p only

Any idea on how fast this encoder is? Is it multithreaded?

[Blue_MiSfit]

@ Mug Funky

My sentiments EXACTLY!!

I had such a headache capturing uncompressed 1080p24 in 8 bit 4:2:2 to a RAID, and then offloading it to a bunch of firewire drives. It takes WAY too much time. Capturing directly into an editing format like CineForm/ DNxHD / ProRes would have been a huge time (and space) saver.

Unfortunately, we were on Final Cut Pro, which at the time didn't have ProRes, and still doesn't have CineForm. DNxHD was a no-go for some reason..

~MiSfit

[tateu]

As with almost every other codec, I have found (as I'm sure many of you have also found) that the FFMpeg implementation is significantly faster than the one in windows Quicktime.

Using QTInput in an avisynth script opened in VirtualDub, pressing F5, I get about 10.5fps. Using FFMpegSource, I get about 19.5fps.

[Blue_MiSfit]

Hmm - that's still very slow. Does Avid have some sort of hardware acceleration??

[tateu]

The Avid appears to have acceleration of some kind. I created 3 test quicktime clips: 23.976 1080p at 185Mb, 120Mb and 36Mb. As mentioned above, they do not play in realtime using FFMpegSource or QTInput. Quicktime player cannot play them in realtime either. The 36Mb file was pure white in quicktime and QTInput. FFMpegSource crashed when trying to play it.

I imported all 3 into a 23.976 1080p project on a 2 year old Avid Meridien Uncompressed system. The 185Mb and 120Mb files fast imported to MXF but the 36Mb was converted to MXF 115. I don't have hi-def out of the Avid but the 185Mb and 120Mb clips played back in real time, atleast to my eyes. The 36Mb file was pure white which means the quicktime codec could not decode the file.

[Mug Funky]

i think the deal with DNxHD and ProRes is they are heavily parallel. from what i've found (which is scant info to say the least), the codecs are extremely similar in philosophy and implementation, though of course apple made a lot more noise about it than Avid did (when they came out with it much earlier).

@ tateu: it'd be interesting to compare the quicktime and ffmpeg implementations of prores, assuming it gets ported eventually. there'll likely be massive gains in quicktime the more cores you have.

[Blue_MiSfit]

By "heavily parallel", do you mean similar, or parallel in the sense of being heavily multithreaded?

I wonder how real-time ProRes or DNxHD 1080p ingest runs real-time??

~Misfit