Two questions about retaining the best quality possible.

[Glass]

Although it feels weird talking about video file quality after hearing about the sad news (RIP DanR and good luck in your future endeavors Dan203 - thank you both for this great program!) there are two things I've been wondering about for quite a while and I figured someone could potentially help out.

Has there been an official confirmation or does anyone know for sure about the minimum video section of not needed stuff you should still keep to make sure none of the portion you actually need gets transcoded? 2 frames? 1 keyframe? I usually leave 3 keyframes before and 3 keyframes after of what I actually want to keep just to feel safe that what I actually want remains untouched, but I get the feeling that might be a bit excessive and if there are many cuts, I feel like I end up with an output video that wastes substantially more disk space than needed.

Also, does combining video files of different quality/properties retain the exact quality of the initial files (except the tiny section they are combined of course)? I mean, let’s say I have an incomplete (45 mins) .ts recording of a TV program and I want to combine it with the last 15 minutes of the same program from a mkv youtube source of lesser quality and different properties (bitrate, resolution etc.) so I have the whole thing.
Would the first 45 mins retain the exact same quality of the .ts recording or since I am combining it with a lower quality video and lots of transcoding will come in play, those 45 mins would end up worse too, so I might as well just keep two videos instead of combining them? Or is there a better way? Thanks!

 

[cp2]

I recall that when seeking to join or combine files of different resolutions VRD may well decline to handle the task. I don't think that it will handle some audio changes either (like AAC / AC3). You are probably better off processing any different sections separately so that all the sections have a common standrard before being combined.

 

[Winnewup]

Hello Glass,
I combine different sources very often. The main part is from ts files and corrupted or missing sections are from other sources. VRD does a really good job in cutting the main source to exactly that frames I want to keep. It doesn't make a visible difference if you keep not needed parts just to avoid recoding. If you would avoid recoding and would be absolutely sure not leaving anything that is needed (at the front of a file) you have to cut at IDR frames; this could end up in some seconds of stuff you don't want. At the end of the file you can cut at P or I or IDR frames without recoding.
In the second step I recode the missing parts from the other source to exactly the same video and audio parameters than the main source. And in the third step I join the parts.
Be careful: if you are talking about ts streams the cut points can be a bit difficult. If the result makes problems at the joining points, it is better not to cut the main source at I frames. This forces VRD to make a recode around the cut points and the result is often better when you are going to join more parts from different or the same source.

Regards
Frank