flybynight wrote: nightstrm wrote:
I'm sure I'll throw out my current encodes and bump up CRF to .66-.68 as soon as Steve announces the 32 and 64GB 3G iPhone later this year. Wouldn't be the first (or second, or third) time I've restarted.
Can you give me a quick (layman's) explanation of why you use CRF at 60-something percent, as opposed to setting the target bitrate at the preset's 2500kbps and using 2-pass encode? I'm still learning about all this stuff and just wondering how the different methods effect quality, file size and encode time (less important since I usually just set it running overnight or while I am at work). Fitting in on my iPhone is not important, mostly quality and reliability of streaming to the @TV.
When are those 10Tb hard drives coming out???
I think I can handle a laymans example. Have you ever encoded in ffmpeg on the command line and watched the bitrate and q numbers change? Q doesn't mean quality, but you can think of it that way. Basically, the encoder watches the bitrate, and adjusts quality to stay within its bitrate parameters. A higher Q value, is lower quality, more compression. With CRF, the encoder works the opposite, it maintains the q, or quality, and will adjust the bitrate to make sure you hit that quality. Before handbrake, I used to encode using CRF. One advantage, is you really don't need 2 pass, since you are not so concerned about file size. The disadvantage is you can have wildly different file sizes. You get a movie like Ratatouille, animation, and pristine digital transfer, it will be like less than 1 gig, depending on your settings. Then you take a movie, like an old western, with film shake, and film scratches, and noise, and the encoder will struggle to keep the quality where you want, and pump the bitrate, you may have a 3gig file for a movie same length.
Thats a laymans answer, anyone feel free to correct me. Also, many settings you see in advance, they don't necessarily make a movie look better, they make it look better at the same bit rate. So you get better quality, at same bit rate, but takes longer to encode. Many settings you can turn off, and just give yourself higher bit rate, if speed of encoding is the issue.
So basically, you use the best settings for you, that give you what you want, balancing what is most important to you, speed of encode, quality, file size/bit rate.