2011-04-09, 02:46
I'm encoding some home videos currently and have had a lot of trouble figuring out why XBMC insists on playing back my 1080p30 videos as 1080p24, and thus dropping frames and causing jerky playback.
I'm using iMovie for my editing and exporting via x264encoder (latest). If I export the source material as 720p30, XBMC plays it back normally. If I export as 1080p24 it also plays it back normally (no dropped frames), but of course isn't as smooth as the 720p30 version.
If I export at 1080p30, XBMC drops frames to maintain 24fps; that is, hitting O shows that the source video is 29.97fps, but it plays it back between 22-25fps, dropping a lot of frames to do so.
mkvinfo on the MKV file shows it is 29.97 fps, and my Linux box plays it back fine in both VLC and mplayer.
I've tried this with the 3.6.0 CHD driver as well as one built from SVN r174. Both exhibit the same problems. The card is a 70015 purchased from Logic Supply about 3 months ago.
Is this a limitation of the Broadcom CHD card, or could I possibly be doing something wrong? I've tried flicking every switch I can think of in the encoder and nothing makes a difference with regard to the jerkiness of the video, besides encoding it as 720p30 or 1080p24.
Here is the log file during the testing. The first two video plays are successful -- the third is the problematic one. It shows no errors in the log, but I assure you it's dropping frames to attempt to maintain 24fps.
I can supply some test video if necessary.
-j
I'm using iMovie for my editing and exporting via x264encoder (latest). If I export the source material as 720p30, XBMC plays it back normally. If I export as 1080p24 it also plays it back normally (no dropped frames), but of course isn't as smooth as the 720p30 version.
If I export at 1080p30, XBMC drops frames to maintain 24fps; that is, hitting O shows that the source video is 29.97fps, but it plays it back between 22-25fps, dropping a lot of frames to do so.
mkvinfo on the MKV file shows it is 29.97 fps, and my Linux box plays it back fine in both VLC and mplayer.
I've tried this with the 3.6.0 CHD driver as well as one built from SVN r174. Both exhibit the same problems. The card is a 70015 purchased from Logic Supply about 3 months ago.
Is this a limitation of the Broadcom CHD card, or could I possibly be doing something wrong? I've tried flicking every switch I can think of in the encoder and nothing makes a difference with regard to the jerkiness of the video, besides encoding it as 720p30 or 1080p24.
Here is the log file during the testing. The first two video plays are successful -- the third is the problematic one. It shows no errors in the log, but I assure you it's dropping frames to attempt to maintain 24fps.
I can supply some test video if necessary.
-j