Aha! So I think what you want is "proxy" editing, which has been discussed some on this list in the past...you might want to search back in the list archive to see how people have done it. You will probably have faster editing and a better end result if you use proxy editing instead of just decreasing the video resolution a bit.
I think the basic idea is something like this before editing: mv myvideo.mpg original-myvideo.mpg ffmpeg -i original-myvideo.mpg [use some video/audio codecs] proxy-myvideo.mpg ln -s proxy-myvideo.mpg myvideo.mpg then open "myvideo.mpg" in cinelerra, do your editing, and when ready to render close cinelerra and do: rm myvideo.mpg ln -s original-myvideo.mpg myvideo.mpg then open cinelerra and it will load up the original video instead of the proxy, and you can render at full quality. As far as what video/audio codecs to use to create the proxy, I don't know, as I haven't done it myself. Maybe mpeg2video at a low bitrate? And to nit-pick (for no good reason), mpeg uses both interframe and intraframe compression ;-) On 5/17/07, Bas Alphenaar <[EMAIL PROTECTED]> wrote:
I want to do this because my computer and Cinelerra can't handle the raw 1080i MPEG-TS stream very well, it's just too slow. This is because MPEG uses interframe compression of course. Because of this I want to re-encode the MPEG-TS to a codec that uses intraframe compression. Dan Streetman wrote: > Not at all, you can do that. For example you could load up the > original 1080i in cinelerra, add "deinterlace" and "translate" effects > (to convert from i to p and 1080 to 720), and then render the file. > There are many render formats that cinelerra can read back, I would > probably stick with mpeg2 (which unfortunately in cinelerra means you > have to render video and audio separately and mplex them back together > before re-loading into cinelerra). > > But again, why do you want to do this? If you are just going to load > the 720p file back into cinelerra, why not just use the 1080i file > directly instead? > > On 5/6/07, Bas Alphenaar <[EMAIL PROTECTED]> wrote: >> I'm not sure I understand the YUV story..... Thanks for the help though! >> But does this mean that it is impossible to convert 1080i HDV to 720p in >> a format that Cinelerra understands? >> >> Dan Streetman wrote: >> > Yes, cinelerra is currently rather limited in what files it can read >> > (in my opinion, at least). What I (used to) do is open the m2t file >> > directly in cinelerra and use the (now removed) 1080to480 effect (only >> > works if you are outputting NTSC) and the translate effect to change >> > from 1080 to 720. You can find the 1080to480 effect in the svn >> > history, it was removed (changed) for some reason quite a while back. >> > It's almost the same as 1080to540 but obviously the vert resolution is >> > different. >> > >> > What I do now however is fix the quicktime colormodel translation >> > because it incorrectly converts the interlaced YUV420 from the input >> > file to the YUV888 (or RBG888, or any of the working formats), so the >> > chroma channels are incorrectly interlaced - zoom in on any area of >> > high motion with high color contrast and you'll see what I am talking >> > about. Unfortunately the quicktime lib doesn't check the input >> > interlacing so I have to hack/hardcode the conversion, which means I >> > can't use it to edit any progressive input that is in YUV420. Note >> > that the output also has to be fixed if you are using YUV4MPEGPIPE >> > output since it (incorrectly) converts back to YUV420 before piping it >> > out. >> > >> > Then, I use frames->fields then translate to resize each field then >> > fields->frames to change back to interlaced 720x480. Of course I had >> > to also change the frames<->fields effects to correctly convert >> > between frames/fields as the default effects double (or half) the >> > vertical resolution for some reason. >> > >> > On 5/2/07, Bas Alphenaar <[EMAIL PROTECTED]> wrote: >> >> Hello, >> >> >> >> A few days ago I posted a message on this mailinglist about the >> >> Cinelerra viewer that crashed. This problem is solved, but I still >> can't >> >> use Cinelerra properly because of another problem. >> >> >> >> I am running Cinelerra r1008 on Gentoo (amd64), I compiled with the >> >> following options: >> >> >> >> ./configure --prefix=/usr --with-buildinfo=svn/recompile --enable-mmx >> >> --enable-3dnow --with-external-ffmpeg >> >> >> >> Quote from my other post: >> >> >> >> > I have an HDV camcorder (Sony HDR-HC1) and I capture the MPEG-TS >> stream >> >> > via Firewire using dvgrab with the HDV patch. >> >> >> >> When the capturing is done, I have a fresh *.m2t file in 1080i. I >> tried >> >> to convert this file to 720p in several ways but none of them works. >> >> >> >> These are the things I tried, at every point I give the command that I >> >> used to create the 720p video and how Cinelerra handled the video: >> >> >> >> ------------------------------ >> >> >> >> 1. ffmpeg H.264 with AVI container >> >> >> >> ffmpeg -i dvgrab-001.m2t -deinterlace -s 1280x720 -vcodec h264 >> -qmin 10 >> >> -qmax 15 -acodec mp3 -ab 256k 1.avi >> >> >> >> The Viewer shows nothing, no sound, the commandline says this: >> >> >> >> new_acodec: couldn't find codec for "" >> >> new_vcodec: couldn't find codec for "h264" >> >> new_acodec: couldn't find codec for "" >> >> new_vcodec: couldn't find codec for "h264" >> >> >> >> (Yes, it is outputted twice) >> >> >> >> ------------------------------ >> >> >> >> 2. ffmpeg H.264 with MOV container >> >> >> >> ffmpeg -i dvgrab-001.m2t -deinterlace -s 1280x720 -vcodec h264 >> -qmin 10 >> >> -qmax 15 -acodec mp3 -ab 256k 2.mov >> >> >> >> The video works and sometimes the sound also works (?), but the >> sound is >> >> not in sync when it works (I am using ALSA). Cinelerra also throws >> this >> >> error in an error window randomly while navigating through the video >> >> with the Viewer: >> >> >> >> virtual int FileMOV::read_frame(VFrame*): >> >> quicktime_read_frame/quicktime_decode_video failed, result: >> >> >> >> >> (http://bugs.cinelerra.org/buglist.cgi?quicksearch=quicktime_read_frame >> >> shows 2 bugs about this problem, so I don't think it can be solved >> >> without somebody who can program) >> >> >> >> ------------------------------ >> >> >> >> 3. ffmpeg H.264 with MOV container (but with AC3 codec) >> >> >> >> ffmpeg -i dvgrab-001.m2t -deinterlace -s 1280x720 -vcodec h264 >> -qmin 10 >> >> -qmax 15 -acodec ac3 ac3.mov >> >> >> >> The video plays in the Viewer, the sound doesn't. The commandline >> shows >> >> this: >> >> >> >> new_acodec: couldn't find codec for "ms " >> >> new_acodec: couldn't find codec for "ms " >> >> new_acodec: couldn't find codec for "ms " >> >> new_acodec: couldn't find codec for "ms " >> >> >> >> ------------------------------ >> >> >> >> 4. mencoder H.264 with AVI container >> >> >> >> mencoder dvgrab-001.m2t -ovc x264 -oac mp3lame -vf >> pp=ci,scale=1280:720 >> >> -o 4.avi >> >> >> >> The Viewer shows nothing and there is no sound, the commandline >> outputs >> >> this: >> >> >> >> new_vcodec: couldn't find codec for "h264" >> >> new_vcodec: couldn't find codec for "h264" >> >> >> >> ------------------------------ >> >> >> >> 5. ffmpeg MJPEG with AVI container >> >> >> >> ffmpeg -i dvgrab-001.m2t -deinterlace -s 1280x720 -vcodec mjpeg >> -acodec >> >> mp3 -ab 256k 5.avi >> >> >> >> No video or sound in the Viewer, can't even move the navigation >> button. >> >> The commandline shows this: >> >> >> >> new_acodec: couldn't find codec for "" >> >> new_acodec: couldn't find codec for "" >> >> new_acodec: couldn't find codec for "" >> >> >> >> ------------------------------ >> >> >> >> Is Cinelerra very picky on the video files it can use or am I making a >> >> mistake here? >> >> >> >> _______________________________________________ >> >> Cinelerra mailing list >> >> Cinelerra@skolelinux.no >> >> https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra >> >> >> > >> > _______________________________________________ >> > Cinelerra mailing list >> > Cinelerra@skolelinux.no >> > https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra >> > >> >> _______________________________________________ >> Cinelerra mailing list >> Cinelerra@skolelinux.no >> https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra >> > > _______________________________________________ > Cinelerra mailing list > Cinelerra@skolelinux.no > https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra > _______________________________________________ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
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