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Code Issues Releases Wiki Activity

1) remove global_timebase

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2) define convert_ts
3) use coded_pts for syncpoint


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@17329 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
ods15 2006-01-06 02:06:22 +00:00
parent a3b18c8f27
commit 877e48ebc9
1 changed files with 15 additions and 18 deletions
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33
DOCS/tech/mpcf.txt
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@ -135,8 +135,6 @@ main header:
stream_count v
max_distance v
max_index_distance v
global_time_base_nom v
global_time_base_denom v
for(i=0; i<256; ){
tmp_flag v
tmp_fields v
@ -258,7 +256,9 @@ info_packet: (optional)
syncpoint:
syncpoint_startcode f(64)
global_timestamp v
coded_pts v
stream = coded_pts % stream_count
global_key_pts = coded_pts/stream_count
back_ptr v
Complete definition:
@ -306,6 +306,10 @@ back_ptr
one keyframe for each stream lies between the syncpoint to which
real_back_ptr points, and the current syncpoint.
global_key_pts
After a syncpoint, last_pts of each stream is to be set to:
last_pts[i] = convert_ts(global_key_pts, timebase[stream], timebase[i])
file_id_string
"nut/multimedia container\0"
@ -383,22 +387,15 @@ time_base_nom / time_base_denom = time_base
29.97 1001 30000
23.976 1001 24000
global_time_base_nom / global_time_base_denom = global_time_base
the length of a timer tick in seconds
global_time_base_nom and global_time_base_denom MUST NOT be 0
global_time_base_nom and global_time_base_denom MUST be relatively prime
global_time_base_denom MUST be < 2^31
convert_ts
To switch from 2 different timebases, the following calculation is
defined:
global_timestamp
timestamp in global_time_base units
when a global_timestamp is encountered the last_pts of all
streams is set to the following:
ln = global_time_base_nom*time_base_denom
sn = global_timestamp
d1 = global_time_base_denom
d2 = time_base_nom
last_pts = (ln/d1*sn + ln%d1*sn/d1)/d2
ln = from_time_base_nom*to_time_base_denom
sn = from_timestamp
d1 = from_time_base_denom
d2 = to_time_base_nom
timestamp = (ln/d1*sn + ln%d1*sn/d1)/d2
Note: this calculation MUST be done with unsigned 64 bit integers, and
is equivalent to (ln*sn)/(d1*d2) but this would require a 96bit integer