I have both VideoReDo and TMPGEnc, Smart-Renderer 4. Of the 2, I prefer and use the TMPGEnc product more frequently. I believe they both have a free trial.
A word of caution if you intend to use "smart-rendered" footage in Vegas. In a recent project involving AVCHD footage (1080_60P from Sony Handycam), I wanted to simply "cut" unwanted material from extremely long (left camcorder on) clips for archiving purposes. Both VRD and TMPGEnc can easily do this. However, neither of the these clips would play well in Vegas--even playback on timeline would hang. For that reason and also that I was in a hurry, I re-rendered to a high bit rate MPEG for archiving those clips.
Thanks all. I'll have to look into which works best. I basically want to join individual songs, all made with the same exact render settings in Vegas as a main concept mp4, and was hoping I could edit each song, one at a time and then join them all together as I'm bound to notice imperfections and bad editing more closely if I do each song as a project. I'm hoping it'll play, without hiccups, at least for that first encode by ewetube. The source footage is old SD, horrid, shaky, dark video, uprezzed to 16x9, 720p within Vegas (I wish I could, but cant' afford BCC8) and I'm using every trick in my book to make the final edit interesting (wouldn't impress you real pros), but when I try to do the whole show as one large clip, I invariably miss little things or create new problems before that final render. I do want the final product to look seamless.
I may try the HDV mpg2 way, if this doesn't work. I experimented with a couple and noticed the file size seemed to stay the same, even when I changed bit rates from 15,000,000 to 8,000,000 and I didn't understand that. btw, these were a huge file size compared to the mp4s, like maybe 10 times.
I appreciate and thank you for all the suggestions!!