rendering over and over

[skipc10]

Using a tool like Ulead Vid Studio, it does a 'rendering' step, even if the source files are MPEG. Does anyone know if there is quality loss when it does this or does it leave them alone? It allows MPEG1 and 2 to be joined too - how does it do this - decode and recode everything? I would think quality would suffer....

[vcdfreak]

Every encoding process suffers a loss. Encoding is another word for reformat+compression. Every time you compress, you lose something. Just like your JPEG file. The encoding process involve a step called DCT (Discrete Cosine Transform) which compresses the data space required to store a picture. The same algorithm is used in JPEG compression. It's lossy.

The Media Studio might retain the original MPEG if your final MPEG format is the same as the your original MPEG format. If the software is smart enough, you might not lose the quality for both file types. You might just lose one of the them (MPEG-1 or MPEG-2) if one of them is similar to your final MPEG format. If the software isn't, you lose more quality.

That's why professional edit with AVI files using Premiere or the like software for video editing.

Hope this helps.