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transcoding for higher bitrate helps weaker codec?


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Is there a solution for lossless or virtually lossless transcoding? That's one of the things that frustrates me about video, coming from a stills background where I could shoot in RAW and edit in TIFF and export JPGs for final delivery. Working with log 4K 422 ProRes files is nice, but it's still like working in a JPG format if every time you export you lose info.

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20 minutes ago, EphraimP said:

Is there a solution for lossless or virtually lossless transcoding? That's one of the things that frustrates me about video, coming from a stills background where I could shoot in RAW and edit in TIFF and export JPGs for final delivery. Working with log 4K 422 ProRes files is nice, but it's still like working in a JPG format if every time you export you lose info.

There are lossless formats, including TIFF image sequences. The downside is that file sizes will be astronomical. What type of intermediates are you using, and can you use a proxy workflow instead? Using proxies instead of uncompressed intermediates will have the same fidelity and be a lot less taxing on hard drives.

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8 minutes ago, KnightsFan said:

There are lossless formats, including TIFF image sequences. The downside is that file sizes will be astronomical. What type of intermediates are you using, and can you use a proxy workflow instead? Using proxies instead of uncompressed intermediates will have the same fidelity and be a lot less taxing on hard drives.

I'm using ProRes from my Ninja V as much as possible. And I've used proxies, so I get how they help speed up a workflow and take pressure off of my processor. I'm more concerned about intermediate deliverables to a third party, such as cutting the best take from a multiple take sequence to send to a client, or storage. If I shoot a long sequence, such as an interview, and decided that say, 75 percent is garbage and 10-25 percent is perfect, it would be nice to cut the crap out and be able to transcode the good stuff for future use/long term storage without losing quality. Does that make sense?

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17 minutes ago, EphraimP said:

I'm using ProRes from my Ninja V as much as possible. And I've used proxies, so I get how they help speed up a workflow and take pressure off of my processor. I'm more concerned about intermediate deliverables to a third party, such as cutting the best take from a multiple take sequence to send to a client, or storage. If I shoot a long sequence, such as an interview, and decided that say, 75 percent is garbage and 10-25 percent is perfect, it would be nice to cut the crap out and be able to transcode the good stuff for future use/long term storage without losing quality. Does that make sense?

Yes, that makes perfect sense. With most codecs you can losslessly trim a portion out. It can be done with ffmpeg, I've done it for archiving GoPro footage from long events. I don't know whether any mainstream editing software can do this--there is an option to "only re-encode when necessary" in Resolve but I haven't tried it. On All-I codecs such as ProRes, this should be possible with cuts on any frame, but with intra-frame codecs, you would begin your trim on a I frame.

Unlike an uncompressed format like your TIFFs, cutting out a portion of a compressed codec won't be lossless across edits. For example, you can't color correct it and maintain your complete fidelity with this method.

On the other side, most codecs will not show any degradation over a single re-encoding. Avoid it when possible, but it's usually not the end of the world if you're not doing it a few times.

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4 minutes ago, KnightsFan said:

Yes, that makes perfect sense. With most codecs you can losslessly trim a portion out. It can be done with ffmpeg, I've done it for archiving GoPro footage from long events. I don't know whether any mainstream editing software can do this--there is an option to "only re-encode when necessary" in Resolve but I haven't tried it. On All-I codecs such as ProRes, this should be possible with cuts on any frame, but with intra-frame codecs, you would begin your trim on a I frame.

Unlike an uncompressed format like your TIFFs, cutting out a portion of a compressed codec won't be lossless across edits. For example, you can't color correct it and maintain your complete fidelity with this method.

On the other side, most codecs will not show any degradation over a single re-encoding. Avoid it when possible, but it's usually not the end of the world if you're not doing it a few times.

Thanks, that's super helpful to know. I've not messed with ffmpeg yet. And sound like another in a million reasons why I need to buckle down learn Resolve. 

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6 hours ago, KnightsFan said:

Yes, that makes perfect sense. With most codecs you can losslessly trim a portion out. It can be done with ffmpeg, I've done it for archiving GoPro footage from long events. I don't know whether any mainstream editing software can do this--there is an option to "only re-encode when necessary" in Resolve but I haven't tried it. On All-I codecs such as ProRes, this should be possible with cuts on any frame, but with intra-frame codecs, you would begin your trim on a I frame.

Unlike an uncompressed format like your TIFFs, cutting out a portion of a compressed codec won't be lossless across edits. For example, you can't color correct it and maintain your complete fidelity with this method.

On the other side, most codecs will not show any degradation over a single re-encoding. Avoid it when possible, but it's usually not the end of the world if you're not doing it a few times.

This kind of thing can be very useful if you have long takes with a high shooting ratio..   one thing is for sports if you're recording in slow-motion and waiting for something cool to happen - you can end up with minutes of footage that are completely useless.  For the purposes of editing I tend to wait until the moment has definitely ended and then stop the take and start a new one.  Then in editing I don't have to scan a long clip (120p takes forever to watch) as I can just look at the end of the clip and see if something good happened.

I haven't hit this issue, but if file sizes are too large (maybe with the P4K / P6K this would be more relevant) then you can split the source clip into multiple pieces and delete the minutes of unused footage.  Hard-drive space might be cheap these days, but recording RAW can add up and it might be worthwhile to trim long clips.

P6K 6K Blackmagic RAW 3:1 is 323 MB/s, which is ~1TB per hour.  6TB internal HDDs are $225, and archival should be on redundant HDDs, which means that the 323MB/s is about $75p/h, or ~$1/minute.  So, if your hourly rate is $75p/h is less than the space you can free up by splitting and deleting un-needed source footage then you can come out ahead.

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1 hour ago, shooter said:

Doesn't a stronger intermediate codec help for grading?

I posed the same question recently, and after my own investigation which involved actually doing this with the short im working on, heres my position on this...

the answer is: yes and no

YES, transcoding to a higher resolution, higher bitrate, etc, format could benefit your work in post IF youre

• doing vfx

• sharpening the footage

*doing other stuff like that, theres lots of benefits

BUT!

NO,

• you wont get some magic out of this process to get more out of your grade per se. what youre doing with color and exposure isnt gonna have more latitude just bc you make your crappy phone footage prores 444. u kno?

thats my take on it, correct me if im wrong guize~!

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4 hours ago, shooter said:

I'm afraid to be misunderstood. Let's take on this example of the bucket. Imagine to replace it for a larger bucket (editing/grading codec). Same portion of water (camera codec). That's my point. 

Doesn't a stronger intermediate codec help for grading?

 

You are substituting one method of encoding for another. The second encoding is going to discard information it deems unnecessary according to whatever optimizations it's algorithms make. In other words, you will lose information that was present in the first encoded sequence. It is not a case of just putting you information into a larger bucket, some of it is going to get spilled in the process.

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6 hours ago, shooter said:

I'm afraid to be misunderstood. Let's take on this example of the bucket. Imagine to replace it for a larger bucket (editing/grading codec). Same portion of water (camera codec). That's my point. 

Doesn't a stronger intermediate codec help for grading?

 

You’d be putting the same amount of water in a larger bucket.

No increase in detail, only an increase in file size.

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