Thank you Carl for your clarification. I obtain good results using -q:v 4 Best, Prof. Flavio Sartoretto gia' Docente di Calcolo Scientifico Universita' Ca' Foscari Venezia
On Fri, May 28, 2021 at 5:24 PM Carl Eugen Hoyos <ceffm...@gmail.com> wrote: > > > > > > > Am 28.05.2021 um 11:44 schrieb Michael Koch <astroelectro...@t-online.de>: > > > > Am 28.05.2021 um 11:25 schrieb Flavio Sartoretto: > >> I use ffmpeg in order to convert fname.flv video to mp4: > >> ffmpeg -i fname.flv -c:v mpeg4 -copyts -loglevel verbose fname.mp4 > >> > >> The video quality of my output is bad. How can I improve it? > > > > Add -q:v 1 to your command line. The number does specify the compression > > ratio. 0 ist best quality and 9 is highest compression. > > This is (nearly) completely wrong: > 9 is still high quality, highest compression happens at a much higher value. > Old MEncoder documentation recommends not use a value lower than 2, sane > values start between 5 and 10. > To Flavio: > The answer to your question depends on your use case: Setting a constant > quantiser as suggested leads to output more similar to constant quality as is > possible with x264 (and newer encoders) and is likely a good idea nowadays, > the alternative is setting a bitrate, this should be combined with two-pass > encoding and leads to the best quality - file size relation (which should be > less relevant if you don’t write to a CD). > > Carl Eugen > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".