Date: Mon, 15 Aug 2016 01:36:06 +0200 From: Polytropon <freebsd@edvax.de> To: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Video DVD quality loss with mencoder/dvdauthor/growisofs Message-ID: <20160815013606.896d920c.freebsd@edvax.de>
next in thread | raw e-mail | index | archive | help
Currently I'm searching for a way to create MPEG files suitable for creating movie DVDs. My source files are SD videos with the following properties: container: AVI video: DivX DX50, 640x360 px, 24 bpp, 25 fps audio: MP3, 44.1 kHz, 2 ch, 128 kbps I'd like to "inflate" the video for DVD resolution. When I use mencoder to do so, the graphics gets "blocky". There are no visible compression artifacts in the source video, but the result is really terrible. I know I cannot "increase quality" when doing 640x360 -> 704x576, but it should not get worse. My solution is a script "avi2dvd" which uses mencoder, dvdauthor and growisofs to prepare the required data structures and then burn them onto DVD+R media. The DVD players I tested them with play the result format, but show the "blocky" video just like a software player (both by checking the .mpg and .vob files), so the postprocessing steps do not introduce that significant quality loss. At its heart, the script contains this step: mencoder -oac lavc -ovc lavc -of mpeg -ofps 25 \ -mpegopts format=dvd -vf scale=704:576,harddup \ -af lavcresample=44100 -srate 44100 \ -lavcopts vcodec=mpeg2video:keyint=15:vrc_buf_size=327:vrc_minrate=1152:vbitrate=1152:vrc_maxrate=1152:acodec=mp2:abitrate=224 \ -o ${MPEGFILE} ${AVIFILE} This reflects the parameters I got from the mplayer documentation on the web where this approach is listed for creating DVD files. But as I said: The quality is terrible. (Sidenote: I will additionally need to experiment with -vf crop in order to deal with mis-aligned video sources.) Can anyone provide a _verified_ method that _does not lower_ the resulting video quality? -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20160815013606.896d920c.freebsd>