Nikon D7000 - transcoding footage for broadcast- PLZ HELP

[andjjs]

Hello everyone,

I'm currently working on a documentary which is being shot with Nikon D7000. I shoot all my footage in 1920*1080 24p (as there is no 25p option). And because I live in Europe I must adjust to European standards - which in case of broadcasting (and I decided to go full HD) are either 1920*1080 50i or 1920*1080 25p.

So, in order to fulfill the standards I must transcode my footage to 1920*1080 25p. My first attempt was to convert the footage (in VirtualDub) using one of the lossless codecs: Lagarith or HuffYUV but unfortunately the files turned out too heavy for Sony Vegas...so:

My question to you is this: What steps should I take in order to transcode my footage and maintain as much quality possible?

(Let me also add that the production house wants the final project in either Apple ProRes or AVID LE DNxHD. I do not work on MAC so ProRes is not an option. Anyway, my ideas are as follows

OPTION 1.

transcode to lagarith (in VirtualDub) -> then transcode to .AVI AVID LE DNxHD (in MPEG Streamclip) -> edit the footage in my target codec and render it to AVID LE DNxHD.

I would like to omit the first step in VirtualDub but I don't know any other good encoders capable of doing straight conversion to AVI/MOV AVID LE DNxHD. (I'm not interested in encoders converting to .MXF as Vegas won't read those). Some might suggest: well, transcode only in MPEG Streamclip! But unfortunately the results are not satisfying. The video isn't really changed, the frames are just doubled. So onto my second solution...

OPTION 2.

transcode the footage to Cineform -> edit in Cineform 25fps and render to .AVI AVID LE DNxHD in Vegas

This step seems the easiest but where do I save more quality guys? Or maybe there are BETTER options. I would be very glad if you helped me out. I'm willing of course to answer all your questions. Thank you! Peace!

Andrzej

[poisondeathray]

(Let me also add that the production house wants the final project in either Apple ProRes or AVID LE DNxHD. I do not work on MAC so ProRes is not an option. Anyway, my ideas are as follows

Prores is an option on PC's now - ffmpeg / ffmbc can encode all the flavours (there are dozens of GUI's for ffmpeg)

I would like to omit the first step in VirtualDub but I don't know any other good encoders capable of doing straight conversion to AVI/MOV AVID LE DNxHD. (I'm not interested in encoders converting to .MXF as Vegas won't read those). Some might suggest: well, transcode only in MPEG Streamclip! But unfortunately the results are not satisfying. The video isn't really changed, the frames are just doubled. So onto my second solution...

ffmpeg can also encode to DNxHD (but only the 8bit variety), but DNxHD, ProRes and cineform are lossy options (albeit "visually lossless") . Most people aren't concerned about the quality loss, can cannot see the difference , unless you go frame by frame and zoom in

Of those 3 intermediates, cineform will be the smoothest to edit in vegas (compared to prores and dnxhd on a PC). It has quality options (e.g. "filmscan2" will give you larger files, but better quality)

Option 3 would be to use a proxy workflow in vegas, since "too heavy to edit" was a concern. Use a search, there are many articles/web pages concerning vegas proxy workflow . Basically it involes making smaller , easier to edit versions of the files, then swap back in the original files (or the 25p uncompressed/lagarith/lossless etc..) after edting. If you swap back in the original (or lossless) assets, technically that will give you better quality than using cineform/dnxhd/prores at the 1st step before editing .

[Cornucopia]

You should be able to install Cineform or DNxHD as VCM/Vfw codecs, which will allow you to use them as codec options from within Virtualdub (it has worked for me before). So then, a suggested workflow could be:

1. Open 24p files in Virtualdub. Go to [Video | FrameRate] and do a Source Rate adjustment, changing framerate to "25.000" fps.
2. Go to [Video | Compression] and change your video codec to one of those 2 above.
3. Try to use "Fast Recompress" mode if operating in YUV colorspace; if not, use "Full Processing Mode" for RGB colorspace.
4. Choose [Audio | NoAudio] (you want to do your 4% timesqueeze in a better audio editor)
5. Save as AVI.
6. Open AVI in Vegas (25p session settings), edit, add back in the timesqueezed audio and Render using same codec (or directly to DNxHD if that's what the production house wants).

Scott

[_Al_]

Yes, and that audio speed change you do within Vegas, use Ctrl+grab the end of audio and drag it so it matches that 25fps video length from Virtual Dub. Vegas will keep the pitch for audio. Vegas used to be audio editor before transformation into videoeditor.

[Cornucopia]

You could use Vegas for that, but I would guess that it isn't optimal quality compared to more dedicated audio editors with modern pitch-correcting timestretch functions. That's why I suggested elsewhere. Depending on your deadline, budget, requirements and perception, Vegas could be good enough for you, though...

Scott

[andjjs]

Thank you guys for all the replies!

Poisondeathray - the idea with proxy files is a great one! I might actually go this way. Though I have one question - perhaps a silly one - if I convert all the files - proxy ones and the smaller intended for editing (let's say I convert them all in VirtualDub) will they all be the exact same length, will VirtualDub be that precise? I'm assuming yes, correct? I would like to save myself the frustration after swapping the files and finding out all is messed up

also thx for letting me know that you can convert files to Prores in Windows. I am familiar with ffmpeg, but honestly I have no idea yet how to use it maybe ffmbc is easier? Thanks for the info though, I probably should give those a try.

Scott - thank you for giving me all the necessary steps in VDub! BUT! If you could PLEASE let me know HOW to install DNxHD as VCM/Vfw codec in VirtualDub I would REALLY appreciate it. I have been searching and searching for a solution unfortunately without any results. A link perhaps would be nice.

_Al_ - concerning audio pitch, how about using some VST audio pitch in real-time? Isn't this a good idea?

Once again, thank you guys for your help!

[poisondeathray]

Poisondeathray - tperhaps a silly one - if I convert all the files - proxy ones and the smaller intended for editing (let's say I convert them all in VirtualDub) will they all be the exact same length, will VirtualDub be that precise? I'm assuming yes, correct? I would like to save myself the frustration after swapping the files and finding out all is messed up

You got to make sure your proxies are the same frame rate as the "swapped in" files. Whatever method you use for the 24p =>25p speedup, use the same method for the proxies

I don't think there is a VFW DNxHD implementation, only through quicktime API, or ffmpeg (8bit variety only) . But you could frameserve out of vdub

I am familiar with ffmpeg, but honestly I have no idea yet how to use it maybe ffmbc is easier?

They are very similar, but ffmbc handles some formats a bit better

[Cornucopia]

Yeah, on further research, I haven't been doing DNxHD En-codes via VFW, just De-codes (have 2 or more QT->AVI wrappers that allow that). pdr is right - there is no native Vfw implementation of the codec. In my memory, I had done AVID Vfw, but upon checking, those were deprecated codecs (DV, Meridian, ABVB, etc), not DNxHD.

So I would go Cineform (or frameserve) out from Vdub into Vegas. Out of Vegas as DNxHD (since Vegas does and has always supported QT).

Scott

[andjjs]

Thx guys! I really appreciate your input. One last thing that bothers me:

My native files are YUV 4:2:0. Cineform upsamples those to 4:2:2 (and I think pro version could go even go up to 4:4:4). Does this result in quality loss like it is in case of going from YUV to RGB? This realm for me is still dark magic What settings would you guys suggest?

Peace!

[poisondeathray]

Thx guys! I really appreciate your input. One last thing that bothers me:

My native files are YUV 4:2:0. Cineform upsamples those to 4:2:2 (and I think pro version could go even go up to 4:4:4). Does this result in quality loss like it is in case of going from YUV to RGB? This realm for me is still dark magic What settings would you guys suggest?

Peace!

It also upsamples to 10bit 4:2:2 (you started with 8bit 4:2:0)

Technically there is a loss whenever you upsample chroma, or convert colorspaces, because it's a deviation from the original. You won't see the difference - actually upsampling in cineform looks better to most people because NLE"s have poor chroma upsamping . Most NLE's upsample better from 4:2:2 than 4:2:0 - they have poor chroma upsampling algorithms. Color edges will look more blocky when upsampling from a 4:2:0 source, compared to a 4:2:2 (upsampled by other program) source.

It doesn't matter, because you will likely be working in RGB on the timeline anyway. (Most color corrections, filters will cause conversion to RGB anyway)

This is standard professional workflow.

[andjjs]

Thx poisondeathray! So let me ask this: doesn't it make more sense to go with 'full processing mode' in VirtualDub in order to go straight to RGB if in fact Vegas will alter the footage to RGB anyway? (I already can assume I'll be doing all sorts of color corrections, effects etc.) Or is it wiser to stick to original YUV colorspace? If you could plz explain in a few words I'd appreciate it.

[poisondeathray]

Thx poisondeathray! So let me ask this: doesn't it make more sense to go with 'full processing mode' in VirtualDub in order to go straight to RGB if in fact Vegas will alter the footage to RGB anyway? (I already can assume I'll be doing all sorts of color corrections, effects etc.) Or is it wiser to stick to original YUV colorspace? If you could plz explain in a few words I'd appreciate it.

If if the desired output from vdub is cineform 10-bit 422, try video=>fast recompress in vdub. This will mean cineform will do the upsampling to YUV 4:2:2 (it does a good job) . If you chose "full processing mode", I think (at least in older versions of vdub), it went to RGB before going to YUV 4:2:2 (extra conversion, extra quality loss)

As mentioned earlier - Vegas (and most NLEs) do a better job with 10bit 422 as a starting point (even if the original source was 8bit 420) . The upsampling is better, and you might introduce less banding from color corrections than if you used the original 8bit 420 video (the intermediate seem to handle grading better)

[andjjs]

Thank you all for your help! Much obliged

Peace!