Public bug reported: Binary package hint: mythtv
The broadcast standard for HDTV in North America (ATSC) is defined as 1920 columns by 1080 rows (lines). However, a limitation of the MPEG-2 video standard is that a video must be encoded using blocks of 16x16 pixels. 1080 is not evenly divisible by 16, so the actual broadcast format is 1920x1088 pixels -- the bottom 8 pixels get cropped off by the playback device. Mythfrontend doesn't seem to be doing this correctly. Most TV stations just encode black in the bottom 8 pixels, but some use a gray bar (my local PBS station, KTCA, currently does this). A black bar usually isn't noticeable, but the gray bar can be quite annoying (note that this gray bar can also appear in transcoded video, so a fix to mythtranscode to crop the video before scaling and re-encoding is also necessary). Another side-effect is that this can cause video to be scaled awkwardly when being displayed on a 16:9 display, since the ratio of the raw video is 16:9.06666... Note that there is (or was) also a 1440x1080/1440x1088 format for 4:3 high-definition video, so any fix should probably just generically apply to any video with 1088 lines. I'm not sure what the story is in Europe or other non-ATSC regions, but since this is a side-effect of a fundamental attribute of MPEG video, the same issue probably exists there too. --- [m...@no5][~]$ lsb_release -rd Description: Ubuntu 8.10 Release: 8.10 [m...@no5][~]$ apt-cache policy mythtv mythtv: Installed: (none) Candidate: 0.21.0+fixes18722-0ubuntu1 Version table: 0.21.0+fixes18722-0ubuntu1 0 500 http://us.archive.ubuntu.com intrepid/multiverse Packages --- ** Affects: mythtv (Ubuntu) Importance: Undecided Status: New -- mythfrontend should crop 1920x1088 video to 1920x1080 https://bugs.launchpad.net/bugs/312159 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs