mirror of https://github.com/mpv-player/mpv
reversing the change to the forw/backw pointers, its somewhat simpler to update it if the forward pointer is first
much more efficient encoding of the frame_code table stream_id -> stream_id_plus1, that way 0 is the special case instead of stream_count and we can be sure the table needs only 8bit per entry replace timestamp_msb by timestamp (and obviously dont code the lsb if the whole is coded) thats simpler and more compact add a msb_timestamp flag to the frame_code[].flags git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@12085 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
michael
parent
ec18d784f3
commit
18ebe6ca92
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@ -67,8 +67,8 @@ u(x) unsigned number encoded in x bits in MSB first order
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Bitstream syntax:
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packet header
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backward ptr v
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forward ptr v
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backward ptr v
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align_byte
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while(not byte aligned)
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@ -88,12 +88,21 @@ main header:
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version v
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stream_count v
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checksum_threshold v
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for(i=0; i<256; i++){
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flags[i] v
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if(flags&64){
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stream_id[i] v
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lsb_size[i] v
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data_size_mul[i] v
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for(i=0; i<256; ){
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tmp_flag v
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tmp_stream v
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tmp_mul v
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tmp_size v
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count v
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for(j=0; j<count; j++, i++){
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flags[i]= tmp_flag;
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stream_id_plus1[i]= tmp_stream;
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data_size_mul[i]= tmp_mul;
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data_size_lsb[i]= tmp_size;
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if(++tmp_size >= tmp_mul){
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tmp_size=0;
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tmp_stream++;
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}
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}
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}
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reserved_bytes
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@ -110,7 +119,7 @@ stream_header:
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time_base_nom v
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time_base_denom v
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msb_timestamp_shift v
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inital_timestamp_predictor v(3)
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initial_timestamp_predictor v(3)
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initial_data_size_predictor v(2)
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fixed_fps u(1)
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index_flag u(1)
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@ -148,14 +157,15 @@ frame
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if(flags[frame_code]&1){
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packet header
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}
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if(stream_id[frame_code]==stream_count){
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if(stream_id_plus1[frame_code]==0){
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stream_id v
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}
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if(frame_type == 2){
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msb_timestamp v
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}
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if((flags[frame_code]&12) == 12){
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lsb_timestamp v
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if(flags[frame_code]&16){
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if(flags[frame_code]&4){
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timestamp v
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}else{
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lsb_timestamp v
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}
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}
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if(flags[frame_code]&2){
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data_size_msb v
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@ -302,30 +312,29 @@ frame_code
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different from the first byte of any startcode
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flags[frame_code]
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the bits of the flags from MSB to LSB are CKKTTDP
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the bits of the flags from MSB to LSB are KKTTTDP
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P is 1 for type 1 and 2 packets, 0 for type 0 packets
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TT is the timestamp_code 00,01,10 use the last timestamp + the first,
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second and third last unique timestamp difference, so if the
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timestamp differences, are +3,+1,+2,+2,+1 then last diff is
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TTT is the timestamp_code, 000,001,010 use the last timestamp + the
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first, second and third last unique timestamp difference, so if
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the timestamp differences, are +3,+1,+2,+2,+1 then last diff is
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+1, second is +2 and third is +3
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if TT is 11, then the timestamp is calculated by
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100,101 mean that the lsb or full timestamp is coded
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if TTT is 100, then the timestamp is calculated by
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mask = (1<<msb_timestamp_shift)-1;
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delta= last_timestamp - mask/2
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timestamp= ((timestamp_lsb-delta)&mask) + delta
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TT must be 11 if packet_type is not 0
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TTT must be 100 or 101 if the packet_type is not 0
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the last timestamp differences are reset to the default values
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from the stream header if a packet of type not 0 in encountered
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if D is 1 then the data_size_msb is coded otherwise data_size_msb is 0
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if D is 1 then data_size_msb is coded, otherwise its 0
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KK is the keyframe_type
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00-> no keyframe,
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01-> keyframe,
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10-> equal to last of the same stream,
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11-> opposite from last of the same stream
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KK must be 00 or 01 if the packet_type is not 0
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if C is 1 then stream_id, data_size_mul and data_size_lsb are not
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stored, but predicted from the last ones
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the value 1000001 (65) is used to mark illegal frame_code bytes, at
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least flags[78] must be 65
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flags=1 can be used to mark illegal frame_code bytes
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frame_code=78 must have flags=1
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frame_type
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0 is indicated by (flags[frame_code]&1)==0
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@ -334,19 +343,14 @@ frame_type
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there SHOULD not be more then 0.5 seconds or 16kbyte of type 0 frames
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wihout a intervening frame of different frame_type
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stream_id[frame_code]
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if its not coded in the main_header then its equal to the last one
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from the main header
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stream_id_plus1[frame_code]
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must be <250
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if its 0 then the stream_id is coded in the frame
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data_size_mul[frame_code]
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if its not coded in the main_header then its equal to the last one
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from the main header
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must be <250
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data_size_lsb[frame_code]
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if its not coded in the main_header then its equal to the last one
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from the main header + 1
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must be <250
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data_size
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@ -360,18 +364,15 @@ data_size
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last and next last are reset to the values stored in the stream header
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if an frame with type > 0 is encountered
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msb_timestamp
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most significant bits of the timestamp, SHOULD be 0 for the first frame
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lsb_timestamp
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least significant bits of the timestamp in time_base precission
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Example: IBBP display order
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keyframe msb_timestamp=0 lsb_timestamp=0 -> timestamp=0
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keyframe timestamp=0 -> timestamp=0
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frame lsb_timestamp=3 -> timestamp=3
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frame lsb_timestamp=1 -> timestamp=1
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frame lsb_timestamp=2 -> timestamp=2
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...
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keyframe msb_timestamp=1 lsb_timestamp=1 -> timestamp=257
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keyframe msb_timestamp=257 -> timestamp=257
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frame lsb_timestamp=255->timestamp=255
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frame lsb_timestamp=0 -> timestamp=256
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frame lsb_timestamp=4 -> timestamp=260
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