Exporting codecs...

Hi,

I recorded something with a GoPro for 60 minutes. Instead of having one 60 min long file, GoPro split it up into many, smaller pieces. Because of that, watching the footage sucks. I would rather have one single file. I understand that I could just take my Laptop and Davinci Resolve Studio, drag all those files onto a timeline, export it, and get one single file. However, what are the "best/right" settings, if I wanted to keep the footage as close to the original, as possible!? Codec and Quality wise.

I would think that the way to do it, is to get an app, analyze the footage (codec and container wise) and then just use the same codec and container, when exporting!? Is that correct? If so, what app can I use to figure out what codec the original footage is?

Thanks,

Frank

Crete simple txt file called mylist.txt which points to your parted files like this (you need full paths with extension):

file '/path/to/file1'
file '/path/to/file2'
file '/path/to/file3'

Then call ffmpeg like this:
ffmpeg -f concat -safe 0 -i path/to/mylist.txt -c copy output/path/output.mp4

Match output extension to your source files: mp4, mov etc.
If files have same format, audio config etc. then it should work fine.

I favor both Cineform and DNx files as Intermediates in a situation like this.

You could try and just cut them together in DR without touching anything else. On export, activate "Bypass re-encode when possible" under the advanced settings.

Crete simple txt file called mylist.txt which points to your parted files like this (you need full paths with extension):

file '/path/to/file1'
file '/path/to/file2'
file '/path/to/file3'

Then call ffmpeg like this:
ffmpeg -f concat -safe 0 -i path/to/mylist.txt -c copy output/path/output.mp4

Match output extension to your source files: mp4, mov etc.
If files have same format, audio config etc. then it should work fine.

Andrew,

Thanks for these suggestions. I first wanted to throw my PC against the TV because I wasn't even able to download a working version of ffmpeg. Not to mention that I am not a "command prompt" guy, if you know what I mean. However, after messing around for a bit and watching a YouTube video, it totally worked!

Even though this was not exactly what I was looking for, It really helps. I would still like to know how to do it in Davinci Resolve because I might cut a few scenes out, here and there...

Thanks again.

In case someone else wants to do the same:

https://www.you tube.com/watch?v=1Xf1DfvVJbs&t=1s

I favor both Cineform and DNx files as Intermediates in a situation like this.

When you do this, can you then go back to the original codec and container!? If so, is there a loss any form or shape, when going back and forth between codecs and containers?

Thanks.

You could try and just cut them together in DR without touching anything else. On export, activate "Bypass re-encode when possible" under the advanced settings.

That setting was already enabled by default, but I still gave it a try. I changed no settings and just hit Render. Took forever. No comparison compared to the ffmpeg method. Only reason I would not prefer ffmpeg is because I would like to get rid of some boring footage while combining a few files...

Thanks.

Worth a try, but it doesn't work for all codecs. Sure ffmpeg is faster!

You either want to do edit or just stick some files on the original format as one

ffmpeg is for 2nd case where you have 100s of files and need to join them as is.
Saying this you can add in/out point for each of the source files in list and ffmpeg will trim it as well. With long GOP codecs it won't be frame accurate though.

file '/source/file1.mp4'
inpoint 00:00:30.00
outpoint 00:12:49.08
file '/source/file2.mp4'
inpoint 00:00:10.00
outpoint 00:10:49.08

Last bit is ms not frames.

ffmpeg PC builds are here: https://ffmpeg.org/download.html#build-windows

In Resolve you just drag files to timeline, trim as you wish and export. For your source Resolve rather won't bypass re-encoding, so you need to pick some export codec and wait for render.

When you do this, can you then go back to the original codec and container!?

You would not want to.

Your GoPro has split the 60min file into a series of smaller clip (about 4G each is because SD card is formatted Fat32.) If you simply put clips on the timeline you may get an audio glitch at clip boundaries once rendered.
Go ahead & put clips on the timeline. Select 'all' then right click & look for option to create a 'Compound Clip'.
You can then render this clip or simply work on as is on the timeline. Tested sometime back with GoPro5 clips and it works perfectly.

Other NLEs (Edius & Vegas for example) automatically join split clips when you import them to the Media Window/Bin. Import not drag & drop. Resolve simply gets round split clips in a different way.

Try Manual & YouTube

You either want to do edit or just stick some files on the original format as one

Kind of both. : ). Now that I know how to "stick" files together using ffmpeg, I am going to do that first. Why not? I mean, the codec and container stay the same, right? If so, I would rather slap all the files (that the GoPro and my Drone split), back together, and then later use Davinci Resolve to edit the new [single] file.

ffmpeg is for 2nd case where you have 100s of files and need to join them as is.
Saying this you can add in/out point for each of the source files in list and ffmpeg will trim it as well. With long GOP codecs it won't be frame accurate though.

file '/source/file1.mp4'
inpoint 00:00:30.00
outpoint 00:12:49.08
file '/source/file2.mp4'
inpoint 00:00:10.00
outpoint 00:10:49.08

Last bit is ms not frames.

Going to look into that.

ffmpeg PC builds are here: https://ffmpeg.org/download.html#build-windows

Thanks.

In Resolve you just drag files to timeline, trim as you wish and export. For your source Resolve rather won't bypass re-encoding, so you need to pick some export codec and wait for render.

I do not mind the render times, especially not with my MacBook Pro M1 Max, or whatever that thing is called. That said, the biggest "mystery" to me are the codecs. I watched a few YT videos that explain what a codec and container is, but this does not really help me to choose the right one.

Thanks.

When you do this, can you then go back to the original codec and container!?

You would not want to.

Why?

Your GoPro has split the 60min file into a series of smaller clip (about 4G each is because SD card is formatted Fat32.) If you simply put clips on the timeline you may get an audio glitch at clip boundaries once rendered.
Go ahead & put clips on the timeline. Select 'all' then right click & look for option to create a 'Compound Clip'.
You can then render this clip or simply work on as is on the timeline. Tested sometime back with GoPro5 clips and it works perfectly.

Other NLEs (Edius & Vegas for example) automatically join split clips when you import them to the Media Window/Bin. Import not drag & drop. Resolve simply gets round split clips in a different way.

Try Manual & YouTube

Good tip, thanks.

When you do this, can you then go back to the original codec and container!?

You would not want to.

Why?

Easier to work with but files are many times bigger.

[/quote]Easier to work with but files are many times bigger.[/quote]

Yeah, that makes sense. I thought that there would be a "problem" such as data loss when going back to the original codec. That said, do you know if I can use ffmpeg to change codecs? I believe this is called "decoding"? Or maybe it is just called concerting, not sure.

Thanks.

EDIT: I used to use a program called 5DtoRGB but it doesn't work anymore. Never tried it on Mac though.

ffmpeg is a transcoder so yes- it's made for changing codecs.

There is muxing ... basically taking long-GOP files and concatenating them together without actually re-encoding.

And there is transcoding where you create a complete new file that is re-encoded.

Long-GOP files can be a bear to edit osickly.

Intraframe like Jim suggested to ProRes, DNx, or Cineform are dramatically bigger for disc space, but in return, edit and grade slickly.

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All of my drones record to Windows fat format cards. Just adding them to a timeline as a group and making that group into a compound clip works perfectly. There is no need to reencode unless you want a more edit friendly editing codec for your footage.

ffmpeg is a transcoder so yes- it's made for changing codecs.

Good to know. However, I am sure I am not going to have the patience to deal with all the command prompt stuff, if you know what I mean. Can you suggest another fast transcoder?

Thanks.

VirtualDubb2.

All of my drones record to Windows fat format cards. Just adding them to a timeline as a group and making that group into a compound clip works perfectly. There is no need to reencode unless you want a more edit friendly editing codec for your footage.

I just looked up what 'compound clip' is and I like it. However, from my understanding it only combines clips on a timeline and not "outside" of Davinci Resolve.

Thanks.

You drag clips to Resolve timeline in required order. You can trim them etc. Once done you go to export and then render out in desired format. You get new final file.

Why?

Because the new Cineform or DNx clips are every bit as good as the original, there's no degradation as there sometimes is with Proxies.

Plus, replacing the one clip with multiple clip segments would be a...problem.

ShutterEncoder might work for you.

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You drag clips to Resolve timeline in required order. You can trim them etc. Once done you go to export and then render out in desired format. You get new final file.

I understand that. However, I am just afraid that my new file format/codec somehow is "worse" than the one I started with. Thats why I thought it would be best to have the option to "export same as source", if you know what I mean!? But I do not see that.

Anyhow, using ffmpeg to stich files together without having to "transcode" them, helps a lot, so I am happy about that. I think I am going to do that with all my files first. Then I am going to learn more about codecs and go from there.

Thanks.

ShutterEncoder might work for you.

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Thanks. Going to check it out.

Why?

Because the new Cineform or DNx clips are every bit as good as the original, there's no degradation as there sometimes is with Proxies.

I see. Let me ask you this then: Davinci Resolve is showing my clip as:

H.265 Main L6.0 59.940 fps 3840 x 2160

If I now want to export the clip as close, if not the same, as the source, do I pick:

Format: mp4
Codec: H.265
Resolution: 3840 x 2160 Ultra HD
Frame Rate: 59.94

I mean, that looks like the same thing to me. However, since the computer has to transcode everything anyway, why not select a codec that is less hard on your system, the next time you edit the footage. Right? So does it make more sense to pick something like this:

Format: Quicktime
Codec: GoPro CineForm (has the name GoPro in it, so it can't be that wrong, ha ha).
Type: YUV 10-bit
Resolution: 3840 x 2160 Ultra HD
Frame Rate: 59.94

Plus, replacing the one clip with multiple clip segments would be a...problem.

What do you mean?

Thanks.

Repeated compression in H.264/265 is stomping much harder on your image quality than DNxHR or Cineform. We did a test with 10 generations of H.264 vs. 10 generations of ProRes (which is in the same class of codecs). H.264 looked like an artistic effect, close to manga, while ProRes was very close to the original.

Repeated compression in H.264/265 is stomping much harder on your image quality than DNxHR or Cineform. We did a test with 10 generations of H.264 vs. 10 generations of ProRes (which is in the same class of codecs). H.264 looked like an artistic effect, close to manga, while ProRes was very close to the original.

I obviously do not understand codecs, ha ha. I thought that when picking the same codec as the source, when exporting, you are not really transcoding the footage, rather than just exporting it. I guess that is not the case. However, how can a "small" program like ffmpeg do that and Davinci Resolve cannot? I mean, if ffmpeg is able to stitch files together without transcoding, and trim them without transcoding, right? Too bad that you need all these command lines in order to do that. Not really my thing you know...

Thanks.

BTW. I do not see prores as an export option in DR.

ProRes export is Mac only, under Windows DR can read it, though.
The rest I'll explain later.

There's a lot of material available on codecs for video post production and it's something we all need to stay up on.

Capture codecs like the long-Gop of H.264/5 are useful because of the massive compression they do saving both writing time & file space via specialized chips in-cam.

They are LOUSY for editing and grading, and re-compressing to them introduces much mangling of pixels.

Intraframe codecs like ProRes, Cineform, and DNx take a lot more space on disc but are both vastly easier for post processing on the system AND can go through several generations prior to any visual degradation.

ffmpeg is designed to "remux" long-Gop media, looking for the i-frames between picture groups and simply concatenating the separate parts. No NLE "exports" as a remux.

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NLEs can export as re-mux and many do it today including Resolve. It's just harder to do with long GOP codecs. Resolve is not a king of it and supports only few codecs as pass through, as it's not most desired feature in tool like Resolve. Edius is probably the best NLE if you looking for this feature (it can do smart export for long GOP mpeg2 for example).

ffmpeg is not really a small programme. It's just very different tool than Resolve.
ffmpeg has big open source community behind it, with 100s of developers. When it comes to 'theoretical' developing power Resolve is no match actually. Just in case of ffmpeg it's based on a developer having a good day and doing free coding in spare time (or having sponsored implementations), so it's not really predictable. Resolve of course is coded by paid developers employed by BM.

I obviously do not understand codecs, ha ha. I thought that when picking the same codec as the source, when exporting, you are not really transcoding the footage, rather than just exporting it. I guess that is not the case. ....

BTW. I do not see prores as an export option in DR.

Typically export= new transcode and it doesn't matter if codec is the same or not.
Sometimes you get pass through option, so untouched frames are exported as 1:1 copy of the source, but this is more of an extra feature for NLEs. Typically mainly I frame based codecs (so ProRes, Cineform, DNxHR etc.) are supported.
On PC you have Cineform or DNxHR which are ProRes equivalents.
Exporting long GOP codecs typically equals some quality loss (depending on bitrate), where for intermediate codecs it can be quite often treated as practically/visually lossless (not mathematically though).

With ProRes you get the 'biggest' loss at the first compression process, subsequent generations are very stable. As an intermediate (aka mezzanine) codec it was designed this way, and I don't doubt that DNxHD/HR and Cineform are at the same level.
With GOP codecs (what's a short GOP codec, BTW?) you get a strong generation loss even after minor changes to the image. Nevertheless, H.265 can be I-frame only (so, non-GOP), in 10 bit with 4:2:2 chroma sampling (even 4:4:4:4) and high data rates. But it'll still need more computing power. If your machine can't decode it by hardware, avoid it.

With ProRes you get the 'biggest' loss at the first compression process, subsequent generations are very stable. As an intermediate (aka mezzanine) codec it was designed this way, and I don't doubt that DNxHD/HR and Cineform are at the same level.

They all behave this way. Also going cross codecs is worse than keeping same one.

I just saw that I still have to reply to few posts, but before I do, one more question:

I saw that I cannot use the same command lines on Mac as on Windows. Can someone please tell me what command line I have to use on a mac to combine mp4 files? That would be great. I know it will take one of you 2 seconds and me a day to figure this out... Here are the command lines I use on my PC:

(for %i in (*.mp4) do @echo file '%i') > mylist.txt

ffmpeg -f concat -i mylist.txt -c copy output.mp4

(for %i in (*.mov) do @echo file '%i') > mylist.txt

ffmpeg -f concat -i mylist.txt -c copy output.mov

thanks.