Transcoding H265 footage to H264 for use in Vegas Pro 14?

Aron-C wrote on 11/12/2019, 12:02 PM

I'm trying to record gameplay footage using AMD's Radeon ReLive software and I want to edit it in SVP 14. I've found that using the HEVC codec leads to significantly improved quality compared to AVC, but there's a problem. When I try to import said HEVC files (with the container being .mp4) into the editing software, it just doesn't work. I've been searching all over the place for answers on how to solve this issue, and I think the solution I've found is a good way of doing it? I'm basically asking for confirmation with this post. So what I'm doing is transcoding the original footage to the H264 codec using FFmpeg. The command line code I'm using is as follows:

ffmpeg -i input.mp4 -c:v libx264 -preset veryslow -crf 10 output.mp4

With the 'veryslow' preset being used for the best possible compression;
And my bitrate set at 10, which is I guess overkill but I just want to make sure it's as close to perfect as possible, without going all the way down to -crf 0.

And after doing this, the footage loads into Vegas perfectly fine. Now, I have no idea if this is a good way of doing it, and I'm not sure if it looks better than recording directly to H264. To me it makes sense, and definitely seems like it, but it could very well be a placebo effect. I've also seen posts where people advised 'remuxing' the files so that Vegas can accept them, but I don't really understand what needs to be done there.

Thanks in advance.

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Aron-C wrote on 11/14/2019, 5:12 AM

Another update: I tried recording a clip using the 'Advanced' output option with the x264 encoder set at the 'ultrafast' preset, and the bitrate set to CRF. This seems to work great, but going anything below 'ultrafast' overloads the encoder and the footage becomes laggy. CRF = 18 has only a slight performance decrease and the quality looks good. So should I use this instead of ReLive? The bitrate is around the same, but I've found CRF = 16 to be almost 100 Mbps with pretty much the same performance hit. Is there any visual difference between x264 and H264?

Musicvid wrote on 11/14/2019, 5:47 AM

Every system is going to behave different, but CRF 20 is a comfortable place to start.

This raises an interesting question, and one in which I hope you'll help research.

Are there advantages to capturing high bitrates using hardware codecs, rather than relatively low bitrates with superior architecture? I don't do game capture so the answer lies outside my comfort zone.

Aron-C wrote on 11/14/2019, 2:13 PM

Understood. I think I've got the answers I was looking for, thanks everyone for helping!

Former user wrote on 11/14/2019, 9:42 PM

Another update: I tried recording a clip using the 'Advanced' output option with the x264 encoder set at the 'ultrafast' preset, and the bitrate set to CRF. This seems to work great, but going anything below 'ultrafast' overloads the encoder and the footage becomes laggy.

X264 (ultrafast) is not high quality, and if it's better quality than what your AMD GPU can do I guess that's related to the real time nature of screen encoding . Has to be able to encode 60fps at 1080p, and AMD GPU's h264 asic is very weak. While you should not see much difference between x264 & AMD GPU encoding at 75MB/s using vegas in non-realtime (quality settings) you will see a difference if settings required for screen encoding at your resolution/fps need to be of lower quality . My recollection is that Polaris/Vega GPU's and above are supposed to be able to encode realtime using Quality setting at 1080p60fps, but in reality it could not

Musicvid wrote on 11/14/2019, 11:24 PM

Again, Ultrafast is the same quality as any other x264 preset, but only at a higher bitrate and file size. For instance, turning off CABAC results in 20% larger files, and is faster to render Once more, our mantra:

Size, Quality, Speed. Pick two.