[MPlayer-dev-eng] Lots of stuff for NUT
Oded Shimon
ods15 at ods15.dyndns.org
Sat Dec 31 21:43:51 CET 2005
On Sat, Dec 31, 2005 at 09:10:08PM +0200, Oded Shimon wrote:
> Attached patch has all these fixes and my new index method.
Some more changes.
The weirdness in my keyframe rule is no more, to hell with the overhead,
it's your fault if you made 10 streams. It still won't be all that much
anyway.
Rule is simple now: "when putting keyframe, If more than max_distance has
passed since last keyframe in this stream, place syncpoint, unless the
back_ptr of this stream in the last syncpoint is zero."
Well, simpler. :)
Syncpoints are back to have their pts being the MTS of the frame right
after.
- ods15
-------------- next part --------------
Index: DOCS/tech/mpcf.txt
===================================================================
RCS file: /cvsroot/mplayer/main/DOCS/tech/mpcf.txt,v
retrieving revision 1.86
diff -u -r1.86 mpcf.txt
--- DOCS/tech/mpcf.txt 22 Dec 2005 05:48:04 -0000 1.86
+++ DOCS/tech/mpcf.txt 31 Dec 2005 20:42:45 -0000
@@ -1,5 +1,5 @@
========================================
-NUT Open Container Format DRAFT 20051118
+NUT Open Container Format DRAFT 20051231
========================================
@@ -21,13 +21,13 @@
Compact
~0.2% overhead, for normal bitrates
- index is <10kb per hour (1 keyframe every 3sec)
+ index is <100kb per hour (1 keyframe every 3sec)
a usual header for a file is about 100 bytes (audio + video headers together)
- a packet header is about ~1-8 bytes
+ a packet header is about ~1-5 bytes
Error resistant
seeking / playback without an index
- headers & index can be repeated
+ headers can be repeated
damaged files can be played back with minimal data loss and fast
resync times
@@ -134,26 +134,31 @@
version v
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
- if(tmp_fields>0) tmp_pts s
- if(tmp_fields>1) tmp_mul v
- if(tmp_fields>2) tmp_stream v
- if(tmp_fields>3) tmp_size v
+ if(tmp_fields>0) tmp_mul v
+ else tmp_mul=1
+ if(tmp_fields>1) tmp_sflag v
+ else tmp_sflag=0
+ if(tmp_fields>2) tmp_pts s
+ else tmp_pts=0
+ if(tmp_fields>3) tmp_stream v
+ else tmp_stream=0
+ if(tmp_fields>4) tmp_size v
else tmp_size=0
- if(tmp_fields>4) tmp_res v
+ if(tmp_fields>5) tmp_res v
else tmp_res=0
- if(tmp_fields>5) count v
+ if(tmp_fields>6) count v
else count= tmp_mul - tmp_size
- for(j=6; j<tmp_fields; j++){
+ for(j=7; j<tmp_fields; j++){
tmp_reserved[i] v
}
for(j=0; j<count && i<256; j++, i++){
flags[i]= tmp_flag;
+ stream_flags[i]= tmp_sflag;
stream_id_plus1[i]= tmp_stream;
data_size_mul[i]= tmp_mul;
data_size_lsb[i]= tmp_size + j;
@@ -214,6 +219,9 @@
if(flags[frame_code]&1){
data_size_msb v
}
+ if(flags[frame_code]&2){
+ coded_stream_flags v
+ }
for(i=0; i<reserved_count[frame_code]; i++)
reserved v
data
@@ -221,12 +229,29 @@
index:
index_startcode f(64)
packet header
- stream_id v
max_pts v
- index_length v
- for(i=0; i<index_length; i++){
- index_pts v
- index_position v
+ syncpoints v
+ for(i=0; i<syncpoints; i++){
+ syncpoint_pts v
+ syncpoint_pos_div8 v
+ }
+ for(i=0; i<stream_count; i++) {
+ j = 0;
+ while (j < syncpoints) {
+ repeat s
+ type = (repeat > 0)
+ repeat = abs(repeat)
+ b = repeat & 1;
+ repeat = (repeat >> 1)+1;
+ if (type) {
+ for(k=0; k<repeat; k++)
+ syncpoint[j+k].stream[i].back_ptr = syncpoint[j-b].pos_div8
+ } else {
+ for(k=0; k<repeat; k++)
+ syncpoint[j+k].stream[i].back_ptr = syncpoint[j+k-b].pos_div8
+ }
+ j += repeat
+ }
}
reserved_bytes
checksum u(32)
@@ -243,6 +268,8 @@
name vb
if(type=="v")
value v
+ else if(type=="s")
+ value s
else
value vb
}
@@ -254,10 +281,12 @@
packet header
info_frame
-sync_point:
- frame_startcode f(64)
+syncpoint:
+ syncpoint_startcode f(64)
global_timestamp v
- back_ptr v
+ for(i=0; i<stream_count; i++){
+ back_ptr[i] v
+ }
Complete definition:
@@ -277,15 +306,13 @@
info_packet
}
while(next_code != main_startcode){
- if(next_code == frame_startcode)
- sync_point
+ if(next_code == syncpoint_startcode)
+ syncpoint
frame
}
}
if (next_code == index_startcode){
- while(!eof){
- index
- }
+ index
index_ptr u(64)
}
@@ -297,12 +324,17 @@
size of the packet data (exactly the distance from the first byte
after the forward_ptr to the first byte of the next packet)
-back_ptr
+back_ptr[stream]
real_back_ptr = back_ptr * 8 + 7
- real_back_ptr must point to a position such that a syncpoint
- startcode begins within the next 8 bytes, and such that at least
- one keyframe for each stream lies between the syncpoint to which
- real_back_ptr points, and the current syncpoint.
+ real_back_ptr must point to a position within 8 bytes of a syncpoint
+ startcode. This syncpoint MUST be the closest syncpoint such that one
+ keyframe for this stream lies between it and the current syncpoint.
+
+ Note: back_ptr can be zero, when the frame immediately following is
+ a keyframe of this stream, or EOR has been set for this stream.
+ back_ptr of a stream where EOR is set should only be zero if no other
+ back_ptr of a non-EOR stream in this syncpoint points to before the
+ EOR.
file_id_string
"nut/multimedia container\0"
@@ -316,13 +348,9 @@
stream_starcode
0x11405BF2F9DBULL + (((uint64_t)('N'<<8) + 'S')<<48)
-frame_startcode
+syncpoint_startcode
0xE4ADEECA4569ULL + (((uint64_t)('N'<<8) + 'K')<<48)
- frame_startcodes SHOULD be placed immediately before a keyframe if the
- previous frame of the same stream was a non-keyframe, unless such
- non-keyframe - keyframe transitions are very frequent
-
index_startcode
0xDD672F23E64EULL + (((uint64_t)('N'<<8) + 'X')<<48)
@@ -333,22 +361,20 @@
NUT version. The current value is 2.
max_distance
- max distance of frame_startcodes, the distance may only be larger if
- there is only a single frame between the two frame_startcodes this can
+ max distance of syncpoints, the distance may only be larger if
+ there is no more than a single frame between the two syncpoints. This can
be used by the demuxer to detect damaged frame headers if the damage
results in too long of a chain
+ Syncpoints MUST be placed immediately before a real (non-EOR) keyframe if
+ more than max_distance passed since the previous keyframe of the same
+ stream. The exception to this is if the back_ptr of this stream in the
+ last syncpoint is zero.
+
SHOULD be set to <=32768 or at least <=65536 unless there is a very
good reason to set it higher, otherwise reasonable error recovery will
be impossible
-max_index_distance
- max distance of keyframes which are represented in the index, the
- distance between consecutive entries A and B may only be larger if
- there are no keyframes within this stream between A and B
- SHOULD be set to <=32768 or at least <=65536 unless there is a very
- good reason to set it higher
-
stream_id
Stream identifier
stream_id MUST be < stream_count
@@ -388,7 +414,7 @@
global_time_base_denom MUST be < 2^31
global_timestamp
- timestamp in global_time_base units
+ syncpoint timestamp in global_time_base units
when a global_timestamp is encountered the last_pts of all
streams is set to the following:
@@ -400,13 +426,16 @@
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
+ global_timestamp MUST be equal to the mts of the frame immediately
+ following the syncpoint, in a common timebase.
+
msb_pts_shift
amount of bits in lsb_pts
MUST be <16
decode_delay
maximum time between input and output for a codec, used to generate
- dts from pts
+ dts and mts from pts
is set to 0 for streams without B-frames, and set to 1 for streams with
B-frames, may be larger for future codecs
@@ -422,17 +451,25 @@
different from the first byte of any startcode
flags[frame_code]
- first of the flags from MSB to LSB are called KD
- if D is 1 then data_size_msb is coded, otherwise data_size_msb is 0
- K is the keyframe_type
- 0 -> no keyframe,
- 1 -> keyframe,
- flags=4 can be used to mark illegal frame_code bytes
- frame_code=78 must have flags=4
- Note: frames MUST NOT depend(1) upon frames prior to the last
- frame_startcode
- Important: depend(1) means dependency on the container level (NUT) not
- dependency on the codec level
+ Bit Name Description
+ 1 data_size_msb if set, data_size_msb is at frame header,
+ otherwise data_size_msb is 0
+ 2 more_flags if set, stream control flags are at frame header.
+ 4 invalid if set, frame_code is invalid.
+
+ frame_code=78 ('N') MUST have flags=64
+
+stream_flags
+ stream_flags is "stream_flags[frame_code] | coded_stream_flags"
+
+ Bit Name Description
+ 1 is_key if set, frame is keyframe
+ 2 end_of_relevance if set, stream has no relevance on
+ presentation until next frame. (EOR)
+
+ EOR frames MUST be zero-length and must be set keyframe. EOR is unset
+ by the first frame following the EOR of the same stream.
+ All streams SHOULD end with EOR.
stream_id_plus1[frame_code]
must be <250
@@ -479,9 +516,17 @@
stream, into which the current pts is inserted and the element with
the smallest value is removed, this is then the current dts
this buffer is initalized with decode_delay -1 elements
- all frames must be monotone, that means a frame
- which occurs later in the stream must have a larger or equal dts
- than an earlier frame
+
+mts
+ muxer timestamp, mts is defined:
+ MIN(pts of this frame and all subsequent frames on this stream)
+ only decode_delay subsuquent frames need to be checked.
+ All frames of all streams MUST have monotone growing mts, in a common
+ timebase.
+ A demuxer can detect stream corruption if mts is out of order. To detect
+ this, dts can be used. With monotone mts, pts of all frames in all
+ streams must be bigger or equal to dts of all previous frames in all
+ streams.
width/height
MUST be set to the coded width/height
@@ -508,23 +553,24 @@
forward_ptr until last byte before the checksum).
max_pts
- The highest pts in the stream.
+ The highest pts in the entire file in global timebase.
+
+syncpoints
+ amount of syncpoints in the file.
-index_pts
- value of the pts of a keyframe relative to the last keyframe
- stored in this index
-
-index_position
- position in bytes of the first byte of a keyframe, relative to the
- last keyframe stored in this index
- there MUST be no keyframe with the same stream_id as this index between
- two consecutive index entries if they are more than max_index_distance
- apart
+syncpoint_pts
+ global_timestamp of the syncpoint referred to in this index entry.
+ relative to global_timestamp of last syncpoint.
+
+syncpoint_pos_div8
+ offset from begginning of file to up to 7 bytes before the syncpoint
+ referred to in this index entry. Relative to position of last
+ syncpoint.
index_ptr
- Length in bytes from the first byte of the first index startcode
- to the first byte of the index_ptr. If there is no index, index_ptr
- MUST NOT be written.
+ Length in bytes from the first byte of the index startcode to the first
+ byte of the index_ptr. If there is no index, index_ptr MUST NOT be
+ written.
id
the ID of the type/name pair, so it is more compact
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