What is Huffyuv?

[VideoFanatic]

I don't understand what this program actually does? Can anyone explain it in plain English?

I use Avisynth with HC Encoder. Could I use Huffyux instead?

[poisondeathray]

It's a lossless codec

In your case, it would be used to speed things up. When you are using slow filters, a 2 pass encode endures the slow filters twice (it's the bottleneck) . By applying those filters to a lossless encode first before the 2pass hcenc encode, often the entire process is much faster because the slow filters are experienced only once

[VideoFanatic]

I only do 1 pass with HC Encoder. Would using Huffyux still speed things up? How much faster would it be? My script currently is 14 FPS.

How exactly do I use Huffyuv with my script and HC Encoder?

[poisondeathray]

If you do 1 pass encodes, then there wil be no benefit

[VideoFanatic]

So if it's of no use to me with Avisynth, I'm just wondering what's the other use for it?

Is it just for losslessly compressing an uncompressed video to half the file size? Or can it losslessly compress an MPEG2 or h264 file?

[davexnet]

It's often used as a capture codec. It's lossless, fast, and compressed.

[manono]

So if it's of no use to me with Avisynth, I'm just wondering what's the other use for it?

Lossless codecs are often used as intermediate files between the source and the destination format. For example, I make multiple passes using CCE. I often have slow filters in the script. Therefore I create a lossless AVI and then use a different AviSynth script on it with AviSource to open that in CCE. The slow script runs once, the fast one five times. Another use is so the quality doesn't degrade over multiple encodes. If I plan on running a series of scripts before doing my final encode in CCE, I'll create a series of lossless AVIs. Apparently you have no use for HuffYUV, but others use lossless codecs quite a lot.

Edit: And just before I posted davexnet mentioned another very important use for them.

[lordsmurf]

If you do 1 pass encodes, then there wil be no benefit

Even that's not necessarily true.

Sometimes it is faster to encode to an intermediary, and then encode that to MPEG later.
Seen it many, many times in the past decade+

[VideoFanatic]

Just wondering how exactly is it faster to encode a video with an Avisynth script with Huffyuv then do a lossy conversion to MPEG2?

[poisondeathray]

If you do 1 pass encodes, then there wil be no benefit

Even that's not necessarily true.

Sometimes it is faster to encode to an intermediary, and then encode that to MPEG later.
Seen it many, many times in the past decade+

Sometimes it is marginally faster, but usually it's actually slower overall when you factor in that you're encoding it twice: once for the intermediate, and again for the real encode

It depends on what encoder you are using , and if/how the encoder uses a lookahead analysis for the 1 pass encode . If there is a complex or long look ahead, then you might benefit from an intermediate. Clearly in manono's situation where he's using multiple passes there is a large gain

Different lossless intermediates can impact encoding speed . For example encoding from ut video codec encodes 5-10% faster than lagarith consistently (depending on what encoder you are using). It's even slightly faster than huffyuv.

[poisondeathray]

Just wondering how exactly is it faster to encode a video with an Avisynth script with Huffyuv then do a lossy conversion to MPEG2?

Try it and time it. There are too many variables to account for

It will definitely speed up overall in 2pass or more encodes when you have slow filter bottlenecks.

But usually it will be slower overall , or neglible benefit on a 1 pass

[sanlyn]

IF you don't want to use lossless Huffyuv or Lagarith when working in AVI, just don't use it. Your AVI's will be about 3 times the size they'd be without compression. Both compressors are very fast operators.