Is there a way to figure out if your x264 settings are overkill?

[slicknick610]

I capture motorcycle races with the Elgato Game Capture HD in 720p 60fps. I use just about the highest bitrate. I have tried to check the x264 settings of the captured video with video help but it doesn't list them. I then take out the commercials and encode it with MeGUI. How do I figure out what settings are overkill vs the source other than the eye test? I think I am using overkill settings just to be safe. I would like the encode to go faster if possible.

[johnmeyer]

The usual way to figure out the best encoding settings is to encode the same 10-15 seconds with half a dozen settings. You then watch them all and choose the one that is the best compromise of quality vs. settings. This tradeoff also includes how long it takes to do the encode.

There is no magic bullet or one-size-fits-all answer: you just do the work and look at the result.

[jagabo]

You can use --psnr or --ssim in x264 to get objective metrics. But those metrics don't match human perception of video quality very well.

[_Al_]

Use CRF 1pass encoding, especially encoding game footage, because bitrate demand can fluctuate rapidly. To guess average bitrate is almost not possible. Even if you do it correctly by some miracle, then there is another capture and you will be off again, searching for optimal bitrate , yet again.

Use CRF encoding mode encoding to quality, not bitrate. So you just need to find out your CRF number that looks good for you. Then you just use that number all the time. Start with CRF 18. Lower number produces better quality but file size gets bigger. Or if you increase that number, quality drops a bit and filesize a bit as well.

It is counter intuitive to presume that encoder can watch the quality. But it does. It compares to the original and that is actually you asked for. So you can let encoder do that.

[slicknick610]

Use CRF 1pass encoding, especially encoding game footage, because bitrate demand can fluctuate rapidly. To guess average bitrate is almost not possible. Even if you do it correctly by some miracle, then there is another capture and you will be off again, searching for optimal bitrate , yet again.

Use CRF encoding mode encoding to quality, not bitrate. So you just need to find out your CRF number that looks good for you. Then you just use that number all the time. Start with CRF 18. Lower number produces better quality but file size gets bigger. Or if you increase that number, quality drops a bit and filesize a bit as well.

It is counter intuitive to presume that encoder can watch the quality. But it does. It compares to the original and that is actually you asked for. So you can let encoder do that.

I am capturing races but good idea I think it still applies. There are parts with a lot of motion and then parts without any like when it shows the points lead. I was actually referring to reference frames and merange and other settings that can really slow down encoding.

[pandy]

But what is your source? Camera?

[slicknick610]

But what is your source? Camera?

Cablebox. HDMI to component converter because my cablebox encrypts the hdmi

[_Al_]

Do your best capturing, best what your device can do, and then , if you must (VideoRedo would cut scenes out etc. without re-compression), encode use CRF method for encoding, for any content. There is millions of people still encoding to a bitrate even if they do not have to. There is just tons of tutorials that uses it on web, it is out there, it is difficult to get rid of that consensus from past. Talking about H.264 encoding with x264. Some encoders, different codecs work differently. Or if there is no way around, like maybe your device that perhaps can capture only to a certain pre-sets, based on bitrate.

Another concern is interlacing. Does that Elgato deinterlaces a content if your content is interlaced? FOX channel broadcasts progressive 60p, I think, but others might not.

[KarMa]

Elgato Game Capture HD probably does not use x264 but instead a codec that's compatible with the H.264 encoding chip that it probably has. Hardware encoding is not as efficient per byte as x264 but hardware encoding can be more energy efficient, free up CPU demand, and make devices cheaper. I have never used this device but it might have Slow/Medium/Fast options that you might be able to toggle.

[jagabo]

The Elgato Game Capture HD uses a hardware h.264 encoder. As with all hardware encoders, it's less efficient than x264 (except maybe at the ultrafast and superfast presets)

[pandy]

But what is your source? Camera?

Cablebox. HDMI to component converter because my cablebox encrypts the hdmi

I assume you can't simply record source using some cable capture card?