Sagittaire
25th May 2008, 18:13
For make BluRay encoding I use x264. x264 use IDR for each GOP and x264 use Close GOP. IDR for each GOP is an obligation for BluRay compliancy? If yes it's possible to make IDR for each GOP with Open GOP?
OpenGOP is really important with relative short GOP like BluRay profil. For example with closegop at 24 frame with 3 pyramidal bframe x264 will use in the best case IbBbPbBbPbBPbBbPbBbPbbP. Last frame is Pframe and the last Bframe will use only Pframe for reference. With openGOP at 24 frames with 3 pyramidal bframes x264 will use in the best case IbBbPbBbPbBPbBbPbBbPbBb. The last frame are bframe with the next Iframe for reference at higher quality than Pframe (only intra with better ratio quantizer). Moreover openGOP is better for keyframe popup (local quality flicking) because bframe use the next high quality Iframe for reference.
Here little example:
OpenGOP is really important with relative short GOP like BluRay profil. For example with closegop at 24 frame with 3 pyramidal bframe x264 will use in the best case IbBbPbBbPbBPbBbPbBbPbbP. Last frame is Pframe and the last Bframe will use only Pframe for reference. With openGOP at 24 frames with 3 pyramidal bframes x264 will use in the best case IbBbPbBbPbBPbBbPbBbPbBb. The last frame are bframe with the next Iframe for reference at higher quality than Pframe (only intra with better ratio quantizer). Moreover openGOP is better for keyframe popup (local quality flicking) because bframe use the next high quality Iframe for reference.
Here little example: