In the case of Blu-ray it's (usually) 1920x1080 24p (usually 12 bits per pixel since it's 4:2:0 coded). Remember, the input to any video encoder be it lossy or lossless is raw uncompressed video. By setting H.264 into a lossless mode, you are disabling all of the perceptual processing that enables the larger reduction in space/bitrate.

The original source h.264 video stream is not losslessly encoded, it is lossy encoded, this is so that it will fit on a Bluray instead of being say 300GB (lossless compression may give you ~50% reduction in size). It's the same thing with H.264 RF 0 (lossless) vs lossy encoding.

To put it another way, FLAC is less efficient than MP3 so anything you encode in FLAC will be larger than the same thing encoded in MP3. This is because FLAC doesn't do any perceptual evaluations. Now if you want to convert that to a lossless format, you decompress it back to 1,411,200 bits/sec (since the audio is 16 bits/channel * 2 channels, * 44.1kHz, it's a fixed size), then run it through the FLAC encoder you'll get a FLAC stream on the order of 900-1000kbps. Now say you take a CD, it's 1,411,200 bits/sec of data, you compress it to MP3, it comes out say, 320,000 bits per second. H.264 rf 0 vs normal settings is the same way. It does this by evaluating the audio to determine what should be perceptually inaudible and not storing that information in the file, hence it's 'lossy'. FLAC is lossless encoding, meaning the output is mathematically identical, where as with MP3, the goal is to be perceptually identical to the source. Well 1) 'x264' is not a codec, it is a video encoder that implements H.264 compression.Ģ) h.264 is highly compressed (by ratio), an uncompressed, 1080p 120 minute movie would be about 500 Gigabytesģ) Lossless compression takes a lot of space, for simplicity, compare FLAC to MP3, MP3 at it's highest settings is about 1/3 the bitrate of FLAC.

There's a few things going on, where to start:

Handbrake and makemkv