Hi Leo > I splited my project into smaller projects to make it easy to handle with a > complex edit.. > > after I render each project, I join them together into another program, and > then render it again with exactly the same settings as used before > (quicktime DV)... but I see that this is resulting in an image with less > quality (kind of a squared image...) > > If the source is quicktime DV and Im rendering to quicktime DV this shouldnt > happen, right?
DV is a lossy compressor, it's just not as lossy as others. Therefore while one would expect some generational loss in sections which have been re-encoded the effect isn't likely to be significant UNLESS the encoding was not optimal. Unfortunately most opensource DV codecs have limitations in their encoder. I did a number of tests about 3 years ago and discovered that both the libdv and ffmpeg DV encoders of the day introduced significant artifacts. Since that time my workflow has changed and this is no longer relevant for me so I don't know the current situation. I do know that libdv's encoder has received very little attention in the years since my tests so I would expect that it still suffers from the problem today. From what I've heard on this list and elsewhere the ffmpeg DV encoder has improved in this time but I don't know to what extent and I have not done any tests myself to quantify this. So it all comes down to which DV codec you're using to make do your intermediate renders. If it's libdv then I would expect there to be noticeable artifacts after the first encode and these will only get worse after the second one. If instead you utilise ffmpeg then maybe things are better. You mentioned using quicktime DV which means you're probably using libquicktime. AFAIK this uses libdv as its DV codec (at least by default) so this may be the root of your problem. Note that we're talking about sections of footage which have to be re-encoded. In terms of Cinelerra such re-encoding has to be done if the input frame is modified in any way by Cinelerra - through the application of transitions, blends, amplitude changes, overlays, effects etc. If you have uneffected sections of footage and their quality is dropping then perhaps Cinelerra is forcing a re-encoding across all frames for some reason. While fixing this won't help the quality of effected frames it will improve the quality of frames which are not being changed. Regards jonathan _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
