iTunes HD Quality vs. Blu-Ray

[AMD Lover]

So why is a iTunes tv episode only like 1.8GB but when I rip the episode off a blu-ray in the same 1080p its like 10GB?

 

Does iTunes compress their videos or something? If they do is iTunes 1080p any better than a DVD??? Or does it meet blu-ray quality?

 

Thanks in advance.

[emosun]

bluray is about the best current quality that can exist for media to be on because of how little they need to compress it. obviously there exist forms of media even better than bluray but bluray is typically the highest quality option for most media.

any online streaming service will HIGHLY compress the data down so it can be streamed to thousand of people without slowing down their service.

[johnt]

Streaming services offer like 10% the bitrate of a physical disc. Most consumers don't care because $500 4K hdr tv baby. Living the dream!

 

Also, the file type can make a significant difference in file size. 

[AshleyAshes]

iTunes and BluRays are both using the h.264 video compression method.  Though BluRays will usually use lossless audio formats like DTS-MA, Dolby Master Audio or even uncompressed LPCM, where as iTunes only uses lossy Dolby Digital AC-3 or AAC.  So for audio, the BluRay wins but few would tell the difference.  For video, the BluRay can use signifigantly higher bitrate since it has an entire 25 or 50 gig disc to use for the content where as streaming has to content with one's internet connection.  So a BluRay can be as high as 54mbps (all streams combined) but iTunes are closer to 5-10mbps.