Verizon FiOS TV → [Channels] Re: MPEG-4 is now being used for the .TV channels

Exactly not what I said. You take an UNCOMPRESSED SOURCE and compress it to MPEG2 it will be a larger file than if you take an UNCOMPRESSED SOURCE and compress it to MPEG4 at the same quality.

If you take any compressed source and compress it to another format - adding EXTRA COMPRESSION - you will wind up with a video of lesser quality no matter the file size

MPEG2 is a COMPRESSED SOURCE. MPEG4 is a COMPRESSED SOURCE. Transcoding one to the other will result in a worse looking video than you started out with even though going from 4 to 2 results in a larger file.

You're really not getting it.

You should ask for help in the A/V forum if you don't understand lossy and lossless A/V file handling. Seems to be going of the rails in this forum.

I'm not sure that you understand the MPEG4 is lossy just like MPEG2. It just has a more efficient compression algorithm resulting in a smaller file/stream-size. They can be converted from one to the other without introducing further loss.

No. They cannot. Every round of compression from MPEG2 to MPEG4 or vice versa removes information. There is no way to prevent this.

Both MPEG2 and MPEG4 are lossy formats. Converting from one lossy format to another introduces more loss. There is no way to have a lossless conversion between lossy formats.

This is unequivocally false information. There's not even a debate on it. It's just wrong. It's not an opinion. It's the science of compression.

The source is compressed. Literally no one distributes uncompressed source material.

Exactly. That's why Verizon taking MPEG2 sources and converting them to MPEG4, or taking MPEG4 sources and converting them to MPEG2 will ALWAYS make for a worse quality picture than Verizon sending the video as it receives it.

No they can not.

Once a source is encoded into either MPEG2 or MPEG4, lossy compression takes place. This means detail (quality) is discarded and can never be recovered. Converting between these formats (or any other lossy-compression format) involves another round of lossy compression where more data is discarded. This is a well known foundational fact.

You can start with any given source and encode that same source using both formats (using the exact same source in both cases). For the same quality the MPEG4 encoding will normally be smaller than MPEG2 encoding. Neither of those compressed formats can ever be uncompressed to match the original source since data was lost in their respective compressions. As a result, it is not possible to convert between the two formats without further degrading quality.

I remember this same thread conversation from 4 years ago.

Hope everyone's doing well in FIOS land!

Haha, are you sitting back and laughing at us Jeep? Good to see you