Does YouTube stream it as pcm or convert it to something else?

Wayne,

I had to delete a space before map to get the scrip to work.

ffmpeg -i input.mp4 -i input.wav -vcodec copy -acodec copy -map 0:0 -map 1:0 output.mov

EricLNZ

In my experience, Youtube always streams a lossy audio codec.

Just made a correction to the ffmpeg command line I posted based on John's comments--another typing error-Ha! Also, be aware that you may have to adjust for audio sync issues that may occur as a result of changing containers. You can easily use Vegas to determine this and make adjustments to the command line accordingly by adding an offset parameter. E.g. if you find the audio is delayed by 10 msec, the command line becomes:

ffmpeg -i input.mp4 -itsoffset .010 -i input.wav -vcodec copy -acodec copy -map 0:0 -map 1:0 output.mov

XAVC Intra is a codec that is native to Vegas, nearly lossless, and should play back smoother than MagicYUV. That might fulfill your needs. If you really want to use an intermediate, then, based on the tests I've done and seen, I would use MagicYUV or XAVC Intra ahead of Cineform.

XAVC Intra is 1080p minimum on my vegas 13. I couldn't find 720p.

XAVC Intra is a codec that is native to Vegas, nearly lossless, and should play back smoother than MagicYUV. That might fulfill your needs. If you really want to use an intermediate, then, based on the tests I've done and seen, I would use MagicYUV or XAVC Intra ahead of Cineform.

XAVC Intra is 1080p minimum on my vegas 13. I couldn't find 720p.

Good point. And it's still not in VP16.

It would be stupid to use 1080p right ? It's more than twice the quantity of pixels...

How are proxies any different than intermediates ?

Edit: sorry, stupid question.

The published resources and the forum search feature are the places to look first for expert answers for any basic questions. See the links under "Other published resources" at the bottom of my signature.

School is out.

Yes, sorry for that last question.

It's not like there's a proper lecture of 5 hours anywhere explaining all the codecs in Vegas in details, what they were meant for, what they work best with etc...

How about the mxf HD422 ? Is it good for intermediates?

Proxies are explained in part 9 of this post.

I recommend editing with the original footage if you can. If that's not smooth enough, and the rest of the tips in that post can't make is smooth enough, then I suggest you use the regular Vegas proxy workflow explained there (1280x720 XDCAM EX proxies with a .sfvp0 files extension) and switch back to the originals for rendering.

I certainly wouldn't upscale 720 to 1080 for intermediate use. If you're determined to use intermediates then I'm struggling to think of a native Vegas codec that supports 720p, is lossless or near-lossless, and plays back "more smoothly than downloaded YouTube AVC". Maybe Sony YUV (in the Video for Windows formats) but I think the files are pretty huge. There are 3rd-party codecs that might fit the bill, like MagicYUV (lossless), Cineform, Avid DNxHD/DNxHR (requires Quicktime), Grass Valley HQ/HQX.

If I have to use an intermediate, I use MagicYUV, but I only use one if I've resized/retimed/deinterlaced footage and want to use it in a project with the new attributes. If my problem was simply that my hardware was overloaded, then I'd definitely use proxies rather than intermediates.

How about the mxf HD422 ? Is it good for intermediates?

In my opinion it's not worth increasing the chroma subsampling to 4:2:2 if your source video is 4:2:0 (which it will be from YouTube).

I think you're at the stage where you need to make some size/performance/quality comparisons of your own, using your system.

For performance, just load the files up with the same FX until playback gets stuttery and then observe the FPS figure next to "Display" below the Video Preview window. I would tend to restart Vegas before each test to level the playing field.

You can test the lossiness of a format like this:

1. Render a file with whatever codec, using settings that match the original.

2. Put it on a track above the original, precisely lined up frame-for-frame.

3. Set your preview properties to Best (Full).

4. Mute/unmute the top track and see for yourself how much it differs from the original.

To make that a bit more scientific:

5. Set the compositing mode of the top track to "Difference".

6. Open a Vectorscope window.

7. Observe the size of the white dot at the centre of the Vectorscope. The smaller the dot, the less lossy the file is that you rendered.

It seems easy. Well, thanks a lot ! I'll try with the original footage, if it's not smooth enough, then I'll try the proxies. And there is still ram preview as last resort. All this should be a lot simplier than intermediates.

Thanks for the comparison method.

Just two last questions :

-Because not all ( although most of) my sources come form youtube, there is often some frame rate and format differences between them, one source file might be 360p/24fps the next one 720/30 fps, then 480/24fps, ect, so when editing with the original footage or with the help of the proxies, could it affect smooth playback? (Most of the time I like to just cut a video without fading and stick the next one aside without fading either.)

-What determines the proxy files' size ? How much bigger than the original footage can they get ?

And a third : Do you sometimes see a difference between the playback (with proxies) and the rendered video ? (I just don't like those intrusive additional frames, or missing frames that I get sometimes, I cut my videos very precisely. Of course using fades solves that kind of problem but usually I need that "instantaneous transition".

"What determines the proxy files' size ? How much bigger than the original footage can they get?"

Vegas Pro's internal proxy files are 35 Mbit/s (fixed to the XDCAM EX video standard).

-Because not all ( although most of) my sources come form youtube, there is often some frame rate and format differences between them, one source file might be 360p/24fps the next one 720/30 fps, then 480/24fps, ect, so when editing with the original footage or with the help of the proxies, could it affect smooth playback? (Most of the time I like to just cut a video without fading and stick the next one aside without fading either.)

You can get different frame rates even from YouTube, since they match the framerate that users upload.

Mixing frame rates can affect smooth playback somewhat.

You need to understand Vegas resampling. Read and absorb #3 here and the posts it links to.

And a third : Do you sometimes see a difference between the playback (with proxies) and the rendered video ? (I just don't like those intrusive additional frames, or missing frames that I get sometimes, I cut my videos very precisely. Of course using fades solves that kind of problem but usually I need that "instantaneous transition".

You shouldn't see any additional or missing frames. Not sure if that's all you're asking. Mixing frame rates can be a bit messy at straight cut transitions.

Thanks marco !

Yes Nick, I was wondering whether the created proxies were or not an exact copy (in another codec of course) of the original files, if they might add one frame, miss one, or create a black frame in order to match length, fps, or something. And so whether the created proxies kept or not the original frame rate of each original file.

"Mixing frame rates can be a bit messy at straight cut transitions."
Yes it always has been a plague for playback stability in my previous works. That and the missing frames, additional frames or artefacts that are too often built in the original files. While playing back the timeline you can't tell if the problem comes from a real problem or just from Vegas having a hard time reading the timeline. Your eyes even get tired and used to these mistake and defects, so you end up having to work again on the file just after rendering. Or even worse: You see the mistakes sometime after you've donne with that work, you discover them when admiring your work with pleasure two weeks after it was published.

I discovered today that Vegas sometimes decides by himself to creates proxy files : Today it created one proxy file while I was reprocessing a 9 MB 6 minutes long 480*640 decade old wmv file consisting of a succession of pictures. I have seen those proxy files from time to time and always though it was some kind of sfk.

And so whether the created proxies kept or not the original frame rate of each original file.

I don't know about Vegas Pro but with VMS the proxy is always 720 30 fps even if your source is PAL 25 fps! Maybe Pro gives you a choice for your proxy format?

Anyway it looks as though you are not downloading 4K so you shouldn't need to use proxies or intermediates.