Author: diego Date: Mon Mar 3 18:00:11 2008 New Revision: 653 Log: misc spelling/wording/grammar fixes Modified: docs/nut.txt Modified: docs/nut.txt ============================================================================== --- docs/nut.txt (original) +++ docs/nut.txt Mon Mar 3 18:00:11 2008 @@ -82,8 +82,8 @@ dts EOR frames End of relevance frames indicate that a given stream is not relevant - for presentation begining with the EOR frame and until the following - keyframe. This is primarely intended for periods were subtitles are + for presentation beginning with the EOR frame and until the following + keyframe. This is primarily intended for periods where subtitles are not displayed. But it is not limited to subtitles. @@ -1023,10 +1023,10 @@ Decoding can only start at a keyframe. T least a granularity of N seconds is wanted, then it is neccessary to have at least 1 keyframe every N seconds in every stream. -Furthermore to start correct "presentation" (after seeking) it is neccessary +Furthermore, to start correct "presentation" (after seeking) it is necessary to have a decoded frame from every stream at approximately the same time. Thus it is important to have closely placed keyframes in all streams at least -once every N seconds. This is equivalent of having back pointers frequently +once every N seconds. This is equivalent to having back pointers frequently short. Good example: Video: .....K...........................................K........... @@ -1045,7 +1045,7 @@ shortest back ptrs: <----------------- In the bad example a player would have to demux and decode half of the video between the 2 keyrames to start correct playback if it favors the shortest -back ptr. +back pointer. The above considerations are not specific to NUT. @@ -1089,15 +1089,15 @@ B. forward seeking 1a. Perform a binary search on the syncpoint timestamps finding the one which is smallest and >= the target timestamp. 1b. Perform a binary search on the syncpoint back pointers finding the - smallest one which has a back ptr >= the position of what was found in 1. + smallest one which has a back pointer >= the position found in 1. 2. Follow the back pointer to the corresponding syncpoint. -Alternatively a demuxer can search for a shorter back ptr (which ensures that -keyframes in all streams are closer together) before 2. +Alternatively a demuxer can search for a shorter back pointer (which ensures +that keyframes in all streams are closer together) before 2. One way to do this for backward seeking is: -if the back ptr is longer than the demuxer wants, step back by half the ptr, -search for another syncpoint and repeat until either the ptr is short enough -or the search went too far. +If the back pointer is longer than the demuxer wants, step back by half the +pointer, search for another syncpoint and repeat until either the pointer is +short enough or the search went too far. Seeking with an index (non-normative):