September 2006 - NUT-devel - lists.mplayerhq.hu

[nut]: r158 - in trunk: libnut/demuxer.c libnut/muxer.c libnut/nut.h libnut/priv.h libnut/reorder.c nututils/demux_avi.c nututils/demux_nut.c nututils/demux_ogg.c nututils/framer_mpeg4.c nututils/framer_vorbis.c nututils/nutindex.c nututils/nutmerge.c nututils/nutmerge.h
by ods15 25 Sep '06

25 Sep '06

Author: ods15 Date: Mon Sep 25 20:43:42 2006 New Revision: 158 Modified: trunk/libnut/demuxer.c trunk/libnut/muxer.c trunk/libnut/nut.h trunk/libnut/priv.h trunk/libnut/reorder.c trunk/nututils/demux_avi.c trunk/nututils/demux_nut.c trunk/nututils/demux_ogg.c trunk/nututils/framer_mpeg4.c trunk/nututils/framer_vorbis.c trunk/nututils/nutindex.c trunk/nututils/nutmerge.c trunk/nututils/nutmerge.h Log: LICENSE -> COPYING Modified: trunk/libnut/demuxer.c ============================================================================== --- trunk/libnut/demuxer.c (original) +++ trunk/libnut/demuxer.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include <inttypes.h> #include <stdlib.h> Modified: trunk/libnut/muxer.c ============================================================================== --- trunk/libnut/muxer.c (original) +++ trunk/libnut/muxer.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include <inttypes.h> #include <stdlib.h> Modified: trunk/libnut/nut.h ============================================================================== --- trunk/libnut/nut.h (original) +++ trunk/libnut/nut.h Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #ifndef _NUT_H #define _NUT_H Modified: trunk/libnut/priv.h ============================================================================== --- trunk/libnut/priv.h (original) +++ trunk/libnut/priv.h Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #ifndef _NUT_PRIV_H #define _NUT_PRIV_H Modified: trunk/libnut/reorder.c ============================================================================== --- trunk/libnut/reorder.c (original) +++ trunk/libnut/reorder.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include <inttypes.h> #include <stdlib.h> Modified: trunk/nututils/demux_avi.c ============================================================================== --- trunk/nututils/demux_avi.c (original) +++ trunk/nututils/demux_avi.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include "nutmerge.h" #include <string.h> Modified: trunk/nututils/demux_nut.c ============================================================================== --- trunk/nututils/demux_nut.c (original) +++ trunk/nututils/demux_nut.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include "nutmerge.h" #define ABS(x) MAX(x,-x) Modified: trunk/nututils/demux_ogg.c ============================================================================== --- trunk/nututils/demux_ogg.c (original) +++ trunk/nututils/demux_ogg.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include <stdio.h> #include <string.h> Modified: trunk/nututils/framer_mpeg4.c ============================================================================== --- trunk/nututils/framer_mpeg4.c (original) +++ trunk/nututils/framer_mpeg4.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include "nutmerge.h" Modified: trunk/nututils/framer_vorbis.c ============================================================================== --- trunk/nututils/framer_vorbis.c (original) +++ trunk/nututils/framer_vorbis.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include <string.h> #include "nutmerge.h" Modified: trunk/nututils/nutindex.c ============================================================================== --- trunk/nututils/nutindex.c (original) +++ trunk/nututils/nutindex.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include <stdio.h> #include <stdlib.h> Modified: trunk/nututils/nutmerge.c ============================================================================== --- trunk/nututils/nutmerge.c (original) +++ trunk/nututils/nutmerge.c Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include "nutmerge.h" #include <math.h> Modified: trunk/nututils/nutmerge.h ============================================================================== --- trunk/nututils/nutmerge.h (original) +++ trunk/nututils/nutmerge.h Mon Sep 25 20:43:42 2006 @@ -1,5 +1,5 @@ // (C) 2005-2006 Oded Shimon -// This file is available under the MIT/X license, see LICENSE +// This file is available under the MIT/X license, see COPYING #include <inttypes.h> #include <stdlib.h>

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[nut]: r157 - in trunk: COPYING LICENSE
by ods15 25 Sep '06

25 Sep '06

Author: ods15 Date: Mon Sep 25 20:41:44 2006 New Revision: 157 Added: trunk/COPYING - copied, changed from r151, /trunk/LICENSE Removed: trunk/LICENSE Log: LICENSE -> COPYING bump year Copied: trunk/COPYING (from r151, /trunk/LICENSE) ============================================================================== --- /trunk/LICENSE (original) +++ trunk/COPYING Mon Sep 25 20:41:44 2006 @@ -1,4 +1,4 @@ -Copyright (c) 2005 Oded Shimon +Copyright (c) 2005-2006 Oded Shimon Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),

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[nut]: r155 - trunk/docs/spec.txt
by ods15 25 Sep '06

25 Sep '06

Author: ods15 Date: Sun Sep 24 15:06:19 2006 New Revision: 155 Added: trunk/docs/spec.txt Log: starting point for readable spec in nut repo Added: trunk/docs/spec.txt ============================================================================== --- (empty file) +++ trunk/docs/spec.txt Sun Sep 24 15:06:19 2006 @@ -0,0 +1,932 @@ +================================== +NUT Open Container Format 20060713 +================================== + + + +Intro: +====== + +Features / goals: + (supported by the format, not necessarily by a specific implementation) + +Simple + use the same encoding for nearly all fields + simple decoding, so slow CPUs (and embedded systems) can handle it + +Extendible + no limit for the possible values of all fields (using universal vlc) + allow adding of new headers in the future + allow adding more fields at the end of headers + +Compact + ~0.2% overhead, for normal bitrates + index is <100kb per hour + a usual header for a file is about 100 bytes (audio + video headers together) + a packet header is about ~1-5 bytes + +Error resistant + seeking / playback without an index + headers & index can be repeated + damaged files can be played back with minimal data loss and fast + resync times + +The spec is frozen. All files following spec will be compatible unless the +spec is unfrozen. + + +Definitions: +============ + +MUST the specific part must be done to conform to this standard +SHOULD it is recommended to be done that way, but not strictly required + + + +Syntax: +======= + +Since NUT heavily uses variable length fields, the simplest way to describe it +is using a pseudocode approach. + + + +Conventions: +============ + +The data types have a name, used in the bitstream syntax description, a short +text description and a pseudocode (functional) definition, optional notes may +follow: + +name (text description) + functional definition + [Optional notes] + +The bitstream syntax elements have a tagname and a functional definition, they +are presented in a bottom up approach, again optional notes may follow and +are reproduced in the tag description: + +name: (optional note) + functional definition + [Optional notes] + +The in-depth tag description follows the bitstream syntax. +The functional definition has a C-like syntax. + + + +Type definitions: +================= + +f(n) (n fixed bits in big-endian order) +u(n) (unsigned number encoded in n bits in MSB-first order) + +v (variable length value, unsigned) + value=0 + do{ + more_data u(1) + data u(7) + value= 128*value + data + }while(more_data) + +s (variable length value, signed) + temp v + temp++ + if(temp&1) value= -(temp>>1) + else value= (temp>>1) + +b (binary data or string, to be use in vb, see below) + for(i=0; i<length; i++){ + data[i] u(8) + } + [Note: strings MUST be encoded in UTF-8] + [Note: the character NUL (U+0000) is not legal within + or at the end of a string.] + +vb (variable length binary data or string) + length v + value b + +t (v coded universal timestamp) + tmp v + id= tmp % time_base_count + value= (tmp / time_base_count) * time_base[id] + + +Bitstream syntax: +================= + +Common elements: +---------------- + +reserved_bytes: + for(i=0; i<forward_ptr - length_of_non_reserved; i++) + reserved u(8) + [a demuxer MUST ignore any reserved bytes + a muxer MUST NOT write any reserved bytes, as this would make it + impossible to add new fields at the end of packets in the future + in a compatible way] + +packet_header + startcode f(64) + forward_ptr v + if(forward_ptr > 4096) + header_checksum u(32) + +packet_footer + reserved_bytes + checksum u(32) + [Note: in index packet, reserved_bytes comes before index_ptr] + +reserved_headers + while(next_byte == 'N' && next_code != main_startcode + && next_code != stream_startcode + && next_code != info_startcode + && next_code != index_startcode + && next_code != syncpoint_startcode){ + packet_header + packet_footer + } + + Headers: + +main header: + version v + stream_count v + max_distance v + time_base_count v + for(i=0; i<time_base_count; i++) + time_base_nom v + time_base_denom v + time_base[i]= time_base_nom/time_base_denom + tmp_pts=0 + tmp_mul=1 + tmp_stream=0 + 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 + else tmp_size=0 + if(tmp_fields>4) tmp_res v + else tmp_res=0 + if(tmp_fields>5) count v + else count= tmp_mul - tmp_size + for(j=6; j<tmp_fields; j++){ + tmp_reserved[i] v + } + for(j=0; j<count && i<256; j++, i++){ + if (i == 'N') { + flags[i]= FLAG_INVALID; + j--; + continue; + } + flags[i]= tmp_flag; + stream_id[i]= tmp_stream; + data_size_mul[i]= tmp_mul; + data_size_lsb[i]= tmp_size + j; + pts_delta[i]= tmp_pts; + reserved_count[i]= tmp_res; + } + } + +stream_header: + stream_id v + stream_class v + fourcc vb + time_base_id v + msb_pts_shift v + max_pts_distance v + decode_delay v + stream_flags v + codec_specific_data vb + if(stream_class == video){ + width v + height v + sample_width v + sample_height v + colorspace_type v + }else if(stream_class == audio){ + samplerate_nom v + samplerate_denom v + channel_count v + } + + Basic Packets: + +frame: + frame_code f(8) + frame_flags= flags[frame_code] + if(frame_flags&FLAG_CODED){ + coded_flags v + frame_flags ^= coded_flags + } + if(frame_flags&FLAG_STREAM_ID){ + stream_id v + } + if(frame_flags&FLAG_CODED_PTS){ + coded_pts v + } + if(frame_flags&FLAG_SIZE_MSB){ + data_size_msb v + } + if(frame_flags&FLAG_RESERVED) + reserved_count[frame_code] v + for(i=0; i<reserved_count[frame_code]; i++) + reserved v + if(frame_flags&FLAG_CHECKSUM){ + checksum u(32) + } + data + +index: + max_pts t + syncpoints v + for(i=0; i<syncpoints; i++){ + syncpoint_pos_div16 v + } + for(i=0; i<stream_count; i++){ + last_pts= -1 + for(j=0; j<syncpoints; ){ + x v + type= x & 1 + x>>=1 + n=j + if(type){ + flag= x & 1 + x>>=1 + while(x--) + has_keyframe[n++][i]=flag + has_keyframe[n++][i]=!flag; + }else{ + while(x != 1){ + has_keyframe[n++][i]=x&1; + x>>=1; + } + } + for(; j<n && j<syncpoints; j++){ + if (!has_keyframe[j][i]) continue + A v + if(!A){ + A v + B v + eor_pts[j][i] = last_pts + A + B + }else + B=0 + keyframe_pts[j][i] = last_pts + A + last_pts += A + B + } + } + } + reserved_bytes + index_ptr u(64) + +info_packet: + stream_id_plus1 v + chapter_id v + chapter_start t + chapter_len v + count v + for(i=0; i<count; i++){ + name vb + value s + if (value==-1){ + type= "UTF-8" + value vb + }else if (value==-2){ + type vb + value vb + }else if (value==-3){ + type= "s" + value s + }else if (value==-4){ + type= "t" + value t + }else if (value<-4){ + type= "r" + value.den= -value-4 + value.num s + }else{ + type= "v" + } + } + +syncpoint: + global_key_pts t + back_ptr_div16 v + + Complete definition: + +file: + file_id_string + while(!eof){ + if(next_byte == 'N'){ + packet_header + switch(startcode){ + case main_startcode: main_header; break; + case stream_startcode:stream_header; break; + case info_startcode: info_packet; break; + case index_startcode: index; break; + case syncpoint_startcode: syncpoint; break; + } + packet_footer + }else + frame + } + +the structure of a undamaged file should look like the following, but +demuxers should be flexible and be able to deal with damaged headers so the +above is a better loop in practice (not to mention its simpler) +note, demuxers MUST be able to deal with new and unknown headers + +file: + file_id_string + while(!eof){ + packet_header, main_header, packet_footer + reserved_headers + for(i=0; i<stream_count; i++){ + packet_header, stream_header, packet_footer + reserved_headers + } + while(next_code == info_startcode){ + packet_header, info_packet, packet_footer + reserved_headers + } + if(next_code == index_startcode){ + packet_header, index_packet, packet_footer + } + if (!eof) while(next_code != main_startcode){ + if(next_code == syncpoint_startcode){ + packet_header, syncpoint, packet_footer + } + frame + reserved_headers + } + } + + +Tag description: +---------------- + +file_id_string + "nut/multimedia container\0" + +*_startcode + all startcodes start with 'N' + +main_startcode + 0x7A561F5F04ADULL + (((uint64_t)('N'<<8) + 'M')<<48) + +stream_starcode + 0x11405BF2F9DBULL + (((uint64_t)('N'<<8) + 'S')<<48) + +syncpoint_startcode + 0xE4ADEECA4569ULL + (((uint64_t)('N'<<8) + 'K')<<48) + +index_startcode + 0xDD672F23E64EULL + (((uint64_t)('N'<<8) + 'X')<<48) + +info_startcode + 0xAB68B596BA78ULL + (((uint64_t)('N'<<8) + 'I')<<48) + +version + NUT version. The current value is 3. All lower values are pre-freeze + +forward_ptr + size of the packet data (exactly the distance from the first byte + after the packet_header to the first byte of the next packet) + +max_distance + max distance between startcodes. If p1 and p2 are the byte + positions of the first byte of two consecutive startcodes, then + p2-p1 MUST be less than or equal to max_distance unless the entire + span from p1 to p2 comprises a single packet or a syncpoint + followed by a single frame. This imposition places efficient upper + bounds on seek operations and allows for the detection of damaged + frame headers, should a chain of frame headers pass max_distance + without encountering any startcode. + + syncpoints 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 + + SHOULD be set to <=32768 + if the stored value is >65536 then max_distance MUST be set to 65536 + + This is also half the max frame size without a checksum after the + frameheader. + + +max_pts_distance + max absoloute difference of pts of new frame from last_pts in the + timebase of the stream, without a checksum after the frameheader. + A frame header MUST include a checksum if abs(pts-last_pts) is + strictly greater than max_pts_distance. + Note that last_pts is not necessarily the pts of the last frame + on the same stream, as it is altered by syncpoint timestamps. + SHOULD NOT be higher than 1/timebase + +stream_id + Stream identifier + stream_id MUST be < stream_count + +stream_class + 0 video + 1 audio + 2 subtiles + 3 userdata + Note: the remaining values are reserved and MUST NOT be used + a demuxer MUST ignore streams with reserved classes + +fourcc + identification for the codec + example: "H264" + MUST contain 2 or 4 bytes, note, this might be increased in the future + if needed + the id values used are the same as in avi, so if a codec uses a specific + fourcc in avi then the same fourcc MUST be used here + +time_base_nom / time_base_denom = time_base + the length of a timer tick in seconds, this MUST be equal to the 1/fps + if FLAG_FIXED_FPS is set + time_base_nom and time_base_denom MUST NOT be 0 + time_base_nom and time_base_denom MUST be relatively prime + time_base_denom MUST be < 2^31 + examples: + fps time_base_nom time_base_denom + 30 1 30 + 29.97 1001 30000 + 23.976 1001 24000 + There MUST NOT be 2 identical timebases in a file. + There SHOULD NOT be more timebases than streams. + +time_base_id + id to time_base table + +convert_ts + To switch from 2 different timebases, the following calculation is + defined: + + 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 + +compare_ts + Compares timestamps from 2 different timebases, + if a is before b then compare_ts(a, b) = -1 + if a is after b then compare_ts(a, b) = 1 + else compare_ts(a, b) = 0 + + Care must be taken that this is done exactly with no rounding errors, + simply casting to float or double and doing the obvious + a*timebase > b*timebase is not compliant or correct, neither is the + same with integers, and + a*a_timebase.num*b_timebase.den > b*b_timebase.num*a_timebase.den + will overflow. One possible implementation which shouldn't overflow + within the range of legal timestamps and timebases is: + + if (convert_ts(a, a_timebase, b_timebase) < b) return -1; + if (convert_ts(b, b_timebase, a_timebase) < a) return 1; + return 0; + +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 + is set to 0 for streams without B-frames, and set to 1 for streams with + B-frames, may be larger for future codecs + decode_delay MUST NOT be set higher than necessary for a codec. + +stream_flags + Bit Name Description + 1 FLAG_FIXED_FPS indicates that the fps is fixed + +codec_specific_data + private global data for a codec (could be huffman tables or ...) + if a codec has a global header it SHOULD be placed in here instead of + at the start of every keyframe + the exact format is specified in the codec spec + for H.264 the NAL units MUST be formated as in a bytestream + (with 00 00 01 prefixes) + +frame_code + the meaning of this byte is stored in the main header + the value 78 ('N') is forbidden to ensure that the byte is always + different from the first byte of any startcode + a muxer SHOULD mark 0x00 and 0xFF as invalid to improve error + detection + +flags[frame_code], frame_flags + Bit Name Description + 1 FLAG_KEY if set, frame is keyframe + 2 FLAG_EOR if set, stream has no relevance on + presentation. (EOR) + 8 FLAG_CODED_PTS if set, coded_pts is in the frame header + 16 FLAG_STREAM_ID if set, stream_id is coded in the frame header + 32 FLAG_SIZE_MSB if set, data_size_msb is at frame header, + otherwise data_size_msb is 0 + 64 FLAG_CHECKSUM if set then the frame header contains a checksum + 128 FLAG_RESERVED if set, reserved_count is coded in the frame header + 4096 FLAG_CODED if set, coded_flags are stored in the frame header. + 8192 FLAG_INVALID if set, frame_code is invalid. + + EOR frames MUST be zero-length and must be set keyframe. + All streams SHOULD end with EOR, where the pts of the EOR indicates the + end presentation time of the final frame. + An EOR set stream is unset by the first content frames. + EOR can only be unset in streams with zero decode_delay . + FLAG_CHECKSUM MUST be set if the frame's data_size is strictly greater than + 2*max_distance or the difference abs(pts-last_pts) is strictly greater than + max_pts_distance (where pts represents this frame's pts and last_pts is + defined as below). + +stream_id[frame_code] + MUST be <250 + +data_size_mul[frame_code] + MUST be <16384 + +data_size_lsb[frame_code] + MUST be <16384 + +pts_delta[frame_code] + MUST be <16384 and >-16384 + +reserved_count[frame_code] + MUST be <256 + +data_size + data_size= data_size_lsb + data_size_msb*data_size_mul; + +coded_pts + if coded_pts < (1<<msb_pts_shift) then it is an lsb + pts, otherwise it is a full pts + (1<<msb_pts_shift) + lsb pts is converted to a full pts by: + mask = (1<<msb_pts_shift)-1; + delta = last_pts - mask/2 + pts = ((pts_lsb-delta)&mask) + delta + +lsb_pts + least significant bits of the pts in time_base precision + Example: IBBP display order + keyframe pts=0 -> pts=0 + frame lsb_pts=3 -> pts=3 + frame lsb_pts=1 -> pts=1 + frame lsb_pts=2 -> pts=2 + ... + keyframe msb_pts=257 -> pts=257 + frame lsb_pts=255 -> pts=255 + frame lsb_pts=0 -> pts=256 + frame lsb_pts=4 -> pts=260 + frame lsb_pts=2 -> pts=258 + frame lsb_pts=3 -> pts=259 + all pts's of keyframes of a single stream MUST be monotone + +dts + dts is calculated by using a decode_delay+1 sized buffer for each + 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 + + Pts of all frames in all streams MUST be bigger or equal to dts of all + previous frames in all streams, compared in common timebase. (EOR + frames are NOT exempt from this rule) + +width/height + MUST be set to the coded width/height, MUST NOT be 0 + +sample_width/sample_height (aspect ratio) + sample_width is the horizontal distance between samples + sample_width and sample_height MUST be relatively prime if not zero + both MUST be 0 if unknown otherwise both MUST be non zero + +colorspace_type + 0 unknown + 1 ITU Rec 624 / ITU Rec 601 Y range: 16..235 Cb/Cr range: 16..240 + 2 ITU Rec 709 Y range: 16..235 Cb/Cr range: 16..240 + 17 ITU Rec 624 / ITU Rec 601 Y range: 0..255 Cb/Cr range: 0..255 + 18 ITU Rec 709 Y range: 0..255 Cb/Cr range: 0..255 + +samplerate_nom / samplerate_denom = samplerate + the number of samples per second, MUST NOT be 0 + +crc32 checksum + Generator polynomial is 0x104C11DB7. Starting value is zero. + +checksum + crc32 checksum + checksum is calculated for the area pointed to by forward_ptr not + including the checksum itself (from first byte after the + packet_header until last byte before the checksum). + for frame headers the checksum contains the framecode byte and all + following bytes upto the checksum itself + +header_checksum + checksum over the startcode and forward pointer + +Syncpoint tags: +--------------- + +back_ptr_div16 + back_ptr = back_ptr_div16 * 16 + 15 + back_ptr must point to a position within 16 bytes of a syncpoint + startcode. This syncpoint MUST be the closest syncpoint such that at + least one keyframe with a pts lower or equal to the original syncpoint's + global_key_pts for all streams lies between it and the current syncpoint. + + A stream where EOR is set is to be ignored for back_ptr. + +global_key_pts + After a syncpoint, last_pts of each stream is to be set to: + last_pts[i] = convert_ts(global_key_pts, time_base[id], time_base[i]) + + global_key_pts MUST be bigger or equal to dts of all past frames across + all streams, and smaller or equal to pts of all future frames. + +Index tags: +----------- + +max_pts + The highest pts in the entire file + +syncpoint_pos_div16 + offset from begginning of file to up to 15 bytes before the syncpoint + referred to in this index entry. Relative to position of last + syncpoint. + +has_keyframe + indicates whether this stream has a keyframe between this syncpoint and + the last syncpoint. + +keyframe_pts + The pts of the first keyframe for this stream in the region between the + 2 syncpoints, in the stream's timebase. (EOR frames are also keyframes) + +eor_pts + Coded only if EOR is set at the position of the syncpoint. The pts of + that EOR. EOR is unset by the first keyframe after it. + +index_ptr + Length in bytes of the entire index, from the first byte of the + startcode until the last byte of the checksum. + Note: A demuxer can use this to find the index when it is written at + EOF, as index_ptr will always be 12 bytes before the end of file if + there is an index at all. + + +Info tags: +---------- + +stream_id_plus1 + Stream this info packet applies to. If zero, packet applies to whole + file. + +chapter_id + Id of chapter this packet applies to. If zero, packet applies to whole + file. Positive chapter_id's are real chapters and MUST NOT overlap. + Negative chapter_id indicate a sub region of file and not a real + chapter. chapter_id MUST be unique to the region it represents. + chapter_id n MUST not be used unless there are at least n chapters in the + file + +chapter_start + timestamp of start of chapter + +chapter_len + Length of chapter in same timebase of chapter_start. + +type + for example: "UTF8" -> string or "JPEG" -> JPEG image + "v" -> unsigned integer + "s" -> signed integer + "r" -> rational + Note: nonstandard fields should be prefixed by "X-" + Note: MUST be less than 6 byte long (might be increased to 64 later) + +info packet types + the name of the info entry, valid names are + "Author" + "Description" + "Copyright" + "Encoder" + the name & version of the software used for encoding + "Title" + "Cover" (allowed types are "PNG" and "JPEG") + image of the (CD, DVD, VHS, ..) cover (preferably PNG or JPEG) + "Source" + "DVD", "VCD", "CD", "MD", "FM radio", "VHS", "TV", "LD" + Optional: appended PAL, NTSC, SECAM, ... in parentheses + "SourceContainer" + "nut", "mkv", "mov", "avi", "ogg", "rm", "mpeg-ps", "mpeg-ts", "raw" + "SourceCodecTag" + the source codec id like a fourcc which was used to store a specific + stream in its SourceContainer + "CaptureDevice" + "BT878", "BT848", "webcam", ... (more exact names are fine too) + "CreationTime" + "2003-01-20 20:13:15Z", ... + (ISO 8601 format, see http://www.cl.cam.ac.uk/~mgk25/iso-time.html) + Note: do not forget the timezone + "Keywords" + "Language" + ISO 639 and ISO 3166 for language/country code + something like "eng" (US english), can be 0 if unknown + and "multi" if several languages + see http://www.loc.gov/standards/iso639-2/englangn.html + and http://www.din.de/gremien/nas/nabd/iso3166ma/codlstp1/en_listp1.html + the language code + "Disposition" + "original", "dub" (translated), "comment", "lyrics", "karaoke" + Note: if someone needs some others, please tell us about them, so we + can add them to the official standard (if they are sane) + Note: nonstandard fields should be prefixed by "X-" + Note: names of fields SHOULD be in English if a word with the same + meaning exists in English + Note: MUST be less than 64 bytes long + +value + value of this name/type pair + +stuffing + 0x80 can be placed in front of any type v entry for stuffing purposes + except the forward_ptr and all fields in the frame header where a + maximum of 8 stuffing bytes per field are allowed + + +Structure: +---------- + +the headers MUST be in exactly the following order (to simplify demuxer design) +main header +stream_header (id=0) +stream_header (id=1) +... +stream_header (id=n) + +headers may be repeated, but if they are, then they MUST all be repeated +together and repeated headers MUST be identical + +Each set of repeated headers not at the beginning or end of the file SHOULD +be stored at the earliest possible position after 2^x where x is +an integer and the file end, so the headers may be repeated at 4102 if that is +the closest position after 2^12=4096 at which the headers can be placed + +Note: this allows an implementation reading the file to locate backup +headers in O(log filesize) time as opposed to O(filesize) + +headers MUST be placed at least at the start of the file and immediately before +the index or at the file end if there is no index +headers MUST be repeated at least twice (so they exist three times in a file) + +there MUST be a sync point immediately before the first frame after any headers + + +Index: +------ + +Note: with realtime streaming, there is no end, so no index there either +Index MAY only be repeated after main headers. +If an index is written anywhere in the file, it MUST be written at end of +file as well. + + +Info: +----- + +If a info packet is stored anywhere then a muxer MUST also store an identical +info packet after every main-stream-header set + +If a demuxer has seen several info packets with the same chapter_id and +stream_id then it MUST ignore all but the one with the highest position in +the file + +demxuxers SHOULD not search the whole file for info packets + +demuxer (non-normative): +------------------------ + +in the absence of a valid header at the beginning, players SHOULD search for +backup headers starting at offset 2^x; for each x players SHOULD end their +search at a particular offset when any startcode is found (including syncpoint) + + + +Semantic requirements: +====================== + +If more than one stream of a given stream class is present, each one SHOULD +have info tags specifying disposition, and if applicable, language. +It often highly improves usability and is therefore strongly encouraged. + +A demuxer MUST NOT demux a stream which contains more than one stream, or which +is wrapped in a structure to facilitate more than one stream or otherwise +duplicate the role of a container. any such file is to be considered invalid. +for example vorbis in ogg in nut is invalid, as is +mpegvideo+mpegaudio in mpeg-ps/ts in nut or dvvideo + dvaudio in dv in nut + + + +Sample code (Public Domain, & untested): +======================================== + +typedef BufferContext{ + uint8_t *buf; + uint8_t *buf_ptr; +}BufferContext; + +static inline uint64_t get_bytes(BufferContext *bc, int count){ + uint64_t val=0; + + assert(count>0 && count<9); + + for(i=0; i<count; i++){ + val <<=8; + val += *(bc->buf_ptr++); + } + + return val; +} + +static inline void put_bytes(BufferContext *bc, int count, uint64_t val){ + uint64_t val=0; + + assert(count>0 && count<9); + + for(i=count-1; i>=0; i--){ + *(bc->buf_ptr++)= val >> (8*i); + } + + return val; +} + +static inline uint64_t get_v(BufferContext *bc){ + uint64_t val= 0; + + for(; space_left(bc) > 0; ){ + int tmp= *(bc->buf_ptr++); + if(tmp&0x80) + val= (val<<7) + tmp - 0x80; + else + return (val<<7) + tmp; + } + + return -1; +} + +static inline int put_v(BufferContext *bc, uint64_t val){ + int i; + + if(space_left(bc) < 9) return -1; + + val &= 0x7FFFFFFFFFFFFFFFULL; // FIXME can only encode upto 63 bits currently + for(i=7; ; i+=7){ + if(val>>i == 0) break; + } + + for(i-=7; i>0; i-=7){ + *(bc->buf_ptr++)= 0x80 | (val>>i); + } + *(bc->buf_ptr++)= val&0x7F; + + return 0; +} + +static int64_t get_dts(int64_t pts, int64_t *pts_cache, int delay, int reset){ + if(reset) memset(pts_cache, -1, delay*sizeof(int64_t)); + + while(delay--){ + int64_t t= pts_cache[delay]; + if(t < pts){ + pts_cache[delay]= pts; + pts= t; + } + } + + return pts; +} + + + +Authors: +======== + +Folks from the MPlayer developers mailing list (http://www.mplayerhq.hu/) +Authors in alphabetical order: (FIXME! Tell us if we left you out) + Beregszaszi, Alex (alex(a)fsn.hu) + Bunkus, Moritz (moritz(a)bunkus.org) + Diedrich, Tobias (ranma+mplayer(a)tdiedrich.de) + Felker, Rich (dalias(a)aerifal.cx) + Franz, Fabian (FabianFranz(a)gmx.de) + Gereoffy, Arpad (arpi(a)thot.banki.hu) + Hess, Andreas (jaska(a)gmx.net) + Niedermayer, Michael (michaelni(a)gmx.at) + Shimon, Oded (ods15(a)ods15.dyndns.org)

4 3

transport stream (for live streaming) = container + protocol IN ONE
by Jörg Hartmann 24 Sep '06

24 Sep '06

You call it "proper unix philosophy" to let the protocol handle priority and retransmission for live streaming and not to care the least for this when designing the container. But you probably know that a protocol needs to know about the content of the container (droppable frames, most important stream/channel/pictures/info parts etc.) to handle that efficiently. And that the overheads of both container and surrounding protocol add up. And you probably also know that transport streams for "live streaming" or "live broadcasting" (like MPEG-TS) are for good reasons designed as both in one: protocol and container. Or INSTEAD of both. So my question is: If you only create a container, and while doing that don't even think of how a live-streaming protocol for its use might look like, why do you think that any non-idiot would use it for live streaming at all - instead of a transport stream that is designed from the start to handle the whole of live streaming? Or if you plan to use it for live streaming: why don't you at least take the protocol part (and how both parts add up to an efficient transport system)into consideration (now and not after 1.0)? Cheers, J.H.

3 2

spec: please rename DTS to what it actually is: DSN
by Jörg Hartmann 24 Sep '06

24 Sep '06

Hi folks, back in May 2004 Rich already found that DTS is a misnomer because it's no time stamp at all. So please call it what it is, nothing else but a decode sequence number. You probably want that people reading your spec do understand as much as possible ... Cheers, J.

2 1

[nut]: r156 - trunk/libnut/demuxer.c
by ods15 24 Sep '06

24 Sep '06

Author: ods15 Date: Sun Sep 24 16:18:27 2006 New Revision: 156 Modified: trunk/libnut/demuxer.c Log: modify get_packet to not recurse on its own but let the caller do it. makes saw_syncpoint more accurate. Modified: trunk/libnut/demuxer.c ============================================================================== --- trunk/libnut/demuxer.c (original) +++ trunk/libnut/demuxer.c Sun Sep 24 16:18:27 2006 @@ -540,7 +540,7 @@ CHECK(get_bytes(nut->i, 1, &tmp)); } else { CHECK(get_header(nut->i, NULL)); - return get_packet(nut, pd, saw_syncpoint); + return 3; } } @@ -697,7 +697,7 @@ nut->seek_status = 0; } - err = get_packet(nut, pd, NULL); + while ((err = get_packet(nut, pd, NULL)) == 3); if (err < 0) { // some error occured! fprintf(stderr, "NUT: %s\n", nut_error(-err)); // rewind as much as possible @@ -1046,8 +1046,11 @@ if (!(nut->seek_status & 1)) while (bctello(nut->i) < end || !end) { int saw_syncpoint; nut_packet_t pd; + buf_before = bctello(nut->i); - CHECK(get_packet(nut, &pd, &saw_syncpoint)); // FIXME we're counting on syncpoint cache!! for the good_key later, and stopper_syncpoint + err = get_packet(nut, &pd, &saw_syncpoint); // FIXME we're counting on syncpoint cache!! for the good_key later, and stopper_syncpoint + if (err == 3) continue; + CHECK(err); if (saw_syncpoint) { if (stopper && !stopper_syncpoint && buf_before > stopper->pos - stopper->back_ptr + 15) { @@ -1131,7 +1134,8 @@ while (bctello(nut->i) < min_pos) { nut_packet_t pd; - CHECK(get_packet(nut, &pd, NULL)); + while ((err = get_packet(nut, &pd, NULL)) == 3); + CHECK(err); push_frame(nut, &pd); CHECK(skip_buffer(nut->i, pd.len)); }

1 0

[nut]: r154 - trunk/libnut/demuxer.c
by ods15 24 Sep '06

24 Sep '06

Author: ods15 Date: Sun Sep 24 14:15:43 2006 New Revision: 154 Modified: trunk/libnut/demuxer.c Log: improove last commit by using first syncpoint when it is prooved to be correct. Modified: trunk/libnut/demuxer.c ============================================================================== --- trunk/libnut/demuxer.c (original) +++ trunk/libnut/demuxer.c Sun Sep 24 14:15:43 2006 @@ -339,6 +339,8 @@ if (sl->s[i].pos > sp.pos) continue; if (sp.pos < sl->s[i].pos + 16) { // syncpoint already in list sl->s[i].pos = sp.pos; + assert(!sl->s[i].pts || sl->s[i].pts == sp.pts); + sl->s[i].pts = sp.pts; if (pts) { for (j = 0; j < nut->stream_count; j++) { assert(!sl->s[i].pts_valid || sl->pts[i * nut->stream_count + j] == pts[j]); @@ -919,7 +921,8 @@ goto err_out; } if (i == 0) { // there isn't any syncpoint smaller than requested - seek_buf(nut->i, nut->last_headers, SEEK_SET); // seeking to "begginning of file", the headers + if (sl->s[0].pts) seek_buf(nut->i, sl->s[0].pos, SEEK_SET); + else seek_buf(nut->i, nut->last_headers, SEEK_SET); // seeking to "begginning of file", the headers clear_dts_cache(nut); nut->last_syncpoint = 0; goto err_out;

1 0

[nut]: r153 - trunk/libnut/demuxer.c
by ods15 24 Sep '06

24 Sep '06

Author: ods15 Date: Sun Sep 24 14:07:19 2006 New Revision: 153 Modified: trunk/libnut/demuxer.c Log: fix long withstanding bug by seeking to headers when going past BOF instead of to syncpoint. Modified: trunk/libnut/demuxer.c ============================================================================== --- trunk/libnut/demuxer.c (original) +++ trunk/libnut/demuxer.c Sun Sep 24 14:07:19 2006 @@ -734,7 +734,7 @@ if (tmp == MAIN_STARTCODE) break; } ERROR(tmp != MAIN_STARTCODE, -ERR_NO_HEADERS); - nut->last_headers = bctello(nut->i); + nut->last_headers = bctello(nut->i) - 8; flush_buf(nut->i); } @@ -919,8 +919,7 @@ goto err_out; } if (i == 0) { // there isn't any syncpoint smaller than requested - int FIXME; // pos might not be accurate - if this function is called when there really is an index - seek_buf(nut->i, sl->s[0].pos, SEEK_SET); // seeking to first syncpoint + seek_buf(nut->i, nut->last_headers, SEEK_SET); // seeking to "begginning of file", the headers clear_dts_cache(nut); nut->last_syncpoint = 0; goto err_out;

1 0

[nut]: r152 - trunk/libnut
by ods15 23 Sep '06

23 Sep '06

Author: ods15 Date: Sat Sep 23 22:57:50 2006 New Revision: 152 Modified: trunk/libnut/ (props changed) Log: ignore libnut.a

1 0

[nut]: r151 - trunk/nututils/nutmerge.c
by ods15 23 Sep '06

23 Sep '06

Author: ods15 Date: Sat Sep 23 22:50:42 2006 New Revision: 151 Modified: trunk/nututils/nutmerge.c Log: update to new libnut API Modified: trunk/nututils/nutmerge.c ============================================================================== --- trunk/nututils/nutmerge.c (original) +++ trunk/nututils/nutmerge.c Sat Sep 23 22:50:42 2006 @@ -129,6 +129,7 @@ mopts.write_index = 1; mopts.fti = ft_default; mopts.max_distance = 32768; + mopts.alloc.malloc = NULL; nut = nut_muxer_init(&mopts, nut_stream, NULL); if (stats) fprintf(stats, "%10s%10s%10s%10s\n", "stream", "len", "pts_diff", "flags");

1 0