h264-stream.js
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/*
* h264-stream
*
*
* Copyright (c) 2013 Brightcove
* All rights reserved.
*/
(function(window) {
var
ExpGolomb = window.videojs.hls.ExpGolomb,
FlvTag = window.videojs.hls.FlvTag,
H264ExtraData = function() {
this.sps = []; // :Array
this.pps = []; // :Array
this.addSPS = function(size) { // :ByteArray
console.assert(size > 0);
var tmp = new Uint8Array(size); // :ByteArray
this.sps.push(tmp);
return tmp;
};
this.addPPS = function(size) { // :ByteArray
console.assert(size);
var tmp = new Uint8Array(size); // :ByteArray
this.pps.push(tmp);
return tmp;
};
this.extraDataExists = function() { // :Boolean
return 0 < this.sps.length;
};
// (sizeOfScalingList:int, expGolomb:ExpGolomb):void
this.scaling_list = function(sizeOfScalingList, expGolomb) {
var
lastScale = 8, // :int
nextScale = 8, // :int
j,
delta_scale; // :int
for (j = 0; j < sizeOfScalingList; ++j) {
if (0 !== nextScale) {
delta_scale = expGolomb.readExpGolomb();
nextScale = (lastScale + delta_scale + 256) % 256;
//useDefaultScalingMatrixFlag = ( j = = 0 && nextScale = = 0 )
}
lastScale = (nextScale === 0) ? lastScale : nextScale;
// scalingList[ j ] = ( nextScale == 0 ) ? lastScale : nextScale;
// lastScale = scalingList[ j ]
}
};
this.getSps0Rbsp = function() { // :ByteArray
// remove emulation bytes. Is this nesessary? is there ever emulation
// bytes in the SPS?
var
spsCount = 0,
sps0 = this.sps[0], // :ByteArray
rbspCount = 0,
s, // :uint
e, // :uint
rbsp, // :ByteArray
o; // :uint
s = 1;
e = sps0.byteLength - 2;
rbsp = new Uint8Array(sps0.byteLength); // new ByteArray();
for (o = s ; o < e ;) {
if (3 !== sps0[o + 2]) {
o += 3;
} else if (0 !== sps0[o + 1]) {
o += 2;
} else if (0 !== sps0[o + 0]) {
o += 1;
} else {
console.log('found emulation bytes');
rbsp.set([0x00, 0x00], rbspCount);
spsCount += 2;
rbspCount += 2;
if (o > s) {
// If there are bytes to write, write them
rbsp.set(sps0.subarray(0, o - s), rbspCount);
spsCount += o - s;
rbspCount += o - s;
}
// skip the emulation bytes
o += 3;
s = o;
}
}
// copy any remaining bytes
rbsp.set(sps0.subarray(spsCount), rbspCount); // sps0.readBytes(rbsp, rbsp.length);
return rbsp;
};
// (pts:uint):FlvTag
this.metaDataTag = function(pts) {
var
tag = new FlvTag(FlvTag.METADATA_TAG), // :FlvTag
expGolomb, // :ExpGolomb
profile_idc, // :int
chroma_format_idc, // :int
imax, // :int
i, // :int
pic_order_cnt_type, // :int
num_ref_frames_in_pic_order_cnt_cycle, // :uint
pic_width_in_mbs_minus1, // :int
pic_height_in_map_units_minus1, // :int
frame_mbs_only_flag, // :int
frame_cropping_flag, // :Boolean
frame_crop_left_offset, // :int
frame_crop_right_offset, // :int
frame_crop_top_offset, // :int
frame_crop_bottom_offset, // :int
width,
height;
tag.dts = pts;
tag.pts = pts;
expGolomb = new ExpGolomb(this.getSps0Rbsp());
profile_idc = expGolomb.readUnsignedByte(); // :int = expGolomb.readUnsignedByte(); // profile_idc u(8)
expGolomb.skipBits(16);// constraint_set[0-5]_flag, u(1), reserved_zero_2bits u(2), level_idc u(8)
expGolomb.skipUnsignedExpGolomb(); // seq_parameter_set_id
if (profile_idc === 100 ||
profile_idc === 110 ||
profile_idc === 122 ||
profile_idc === 244 ||
profile_idc === 44 ||
profile_idc === 83 ||
profile_idc === 86 ||
profile_idc === 118 ||
profile_idc === 128) {
chroma_format_idc = expGolomb.readUnsignedExpGolomb();
if (3 === chroma_format_idc) {
expGolomb.skipBits(1); // separate_colour_plane_flag
}
expGolomb.skipUnsignedExpGolomb(); // bit_depth_luma_minus8
expGolomb.skipUnsignedExpGolomb(); // bit_depth_chroma_minus8
expGolomb.skipBits(1); // qpprime_y_zero_transform_bypass_flag
if (expGolomb.readBoolean()) { // seq_scaling_matrix_present_flag
imax = (chroma_format_idc !== 3) ? 8 : 12;
for (i = 0 ; i < imax ; ++i) {
if (expGolomb.readBoolean()) { // seq_scaling_list_present_flag[ i ]
if (i < 6) {
this.scaling_list(16, expGolomb);
} else {
this.scaling_list(64, expGolomb);
}
}
}
}
}
expGolomb.skipUnsignedExpGolomb(); // log2_max_frame_num_minus4
pic_order_cnt_type = expGolomb.readUnsignedExpGolomb();
if ( 0 === pic_order_cnt_type ) {
expGolomb.readUnsignedExpGolomb(); //log2_max_pic_order_cnt_lsb_minus4
} else if ( 1 === pic_order_cnt_type ) {
expGolomb.skipBits(1); // delta_pic_order_always_zero_flag
expGolomb.skipExpGolomb(); // offset_for_non_ref_pic
expGolomb.skipExpGolomb(); // offset_for_top_to_bottom_field
num_ref_frames_in_pic_order_cnt_cycle = expGolomb.readUnsignedExpGolomb();
for(i = 0 ; i < num_ref_frames_in_pic_order_cnt_cycle ; ++i) {
expGolomb.skipExpGolomb(); // offset_for_ref_frame[ i ]
}
}
expGolomb.skipUnsignedExpGolomb(); // max_num_ref_frames
expGolomb.skipBits(1); // gaps_in_frame_num_value_allowed_flag
pic_width_in_mbs_minus1 = expGolomb.readUnsignedExpGolomb();
pic_height_in_map_units_minus1 = expGolomb.readUnsignedExpGolomb();
frame_mbs_only_flag = expGolomb.readBits(1);
if (0 === frame_mbs_only_flag) {
expGolomb.skipBits(1); // mb_adaptive_frame_field_flag
}
expGolomb.skipBits(1); // direct_8x8_inference_flag
frame_cropping_flag = expGolomb.readBoolean();
if (frame_cropping_flag) {
frame_crop_left_offset = expGolomb.readUnsignedExpGolomb();
frame_crop_right_offset = expGolomb.readUnsignedExpGolomb();
frame_crop_top_offset = expGolomb.readUnsignedExpGolomb();
frame_crop_bottom_offset = expGolomb.readUnsignedExpGolomb();
}
width = ((pic_width_in_mbs_minus1 +1)*16) - frame_crop_left_offset*2 - frame_crop_right_offset*2;
height = ((2 - frame_mbs_only_flag)* (pic_height_in_map_units_minus1 +1) * 16) - (frame_crop_top_offset * 2) - (frame_crop_bottom_offset * 2);
tag.writeMetaDataDouble("videocodecid", 7);
tag.writeMetaDataDouble("width", width);
tag.writeMetaDataDouble("height", height);
// tag.writeMetaDataDouble("videodatarate", 0 );
// tag.writeMetaDataDouble("framerate", 0);
return tag;
};
// (pts:uint):FlvTag
this.extraDataTag = function(pts) {
var
i,
tag = new FlvTag(FlvTag.VIDEO_TAG,true);
tag.dts = pts;
tag.pts = pts;
tag.writeByte(0x01);// version
tag.writeByte(this.sps[0][1]);// profile
tag.writeByte(this.sps[0][2]);// compatibility
tag.writeByte(this.sps[0][3]);// level
tag.writeByte(0xFC | 0x03); // reserved (6 bits), NULA length size - 1 (2 bits)
tag.writeByte(0xE0 | 0x01 ); // reserved (3 bits), num of SPS (5 bits)
tag.writeShort( this.sps[0].length ); // data of SPS
tag.writeBytes( this.sps[0] ); // SPS
tag.writeByte( this.pps.length ); // num of PPS (will there ever be more that 1 PPS?)
for (i = 0 ; i < this.pps.length ; ++i) {
tag.writeShort(this.pps[i].length); // 2 bytes for length of PPS
tag.writeBytes(this.pps[i]); // data of PPS
}
return tag;
};
},
// incomplete, see Table 7.1 of ITU-T H.264 for 12-32
NALUnitType = {
unspecified: 0,
slice_layer_without_partitioning_rbsp_non_idr: 1,
slice_data_partition_a_layer_rbsp: 2,
slice_data_partition_b_layer_rbsp: 3,
slice_data_partition_c_layer_rbsp: 4,
slice_layer_without_partitioning_rbsp_idr: 5,
sei_rbsp: 6,
seq_parameter_set_rbsp: 7,
pic_parameter_set_rbsp: 8,
access_unit_delimiter_rbsp: 9,
end_of_seq_rbsp: 10,
end_of_stream_rbsp: 11
};
window.videojs.hls.H264Stream = function() {
var
next_pts, // :uint;
next_dts, // :uint;
pts_delta = -1, // :int
h264Frame, // :FlvTag
oldExtraData = new H264ExtraData(), // :H264ExtraData
newExtraData = new H264ExtraData(), // :H264ExtraData
nalUnitType = -1, // :int
state; // :uint;
this.tags = [];
//(pts:uint, dts:uint, dataAligned:Boolean):void
this.setNextTimeStamp = function(pts, dts, dataAligned) {
if (0>pts_delta) {
// We assume the very first pts is less than 0x8FFFFFFF (max signed
// int32)
pts_delta = pts;
}
// We could end up with a DTS less than 0 here. We need to deal with that!
next_pts = pts - pts_delta;
next_dts = dts - pts_delta;
// If data is aligned, flush all internal buffers
if (dataAligned) {
this.finishFrame();
}
};
this.finishFrame = function() {
console.log('finish frame');
if (h264Frame) {
// Push SPS before EVERY IDR frame fo seeking
if (newExtraData.extraDataExists()) {
oldExtraData = newExtraData;
newExtraData = new H264ExtraData();
}
if (h264Frame.keyFrame) {
// Push extra data on every IDR frame in case we did a stream change + seek
this.tags.push(oldExtraData.metaDataTag(h264Frame.pts));
this.tags.push(oldExtraData.extraDataTag(h264Frame.pts));
}
h264Frame.endNalUnit();
this.tags.push(h264Frame);
}
h264Frame = null;
nalUnitType = -1;
state = 0;
};
// (data:ByteArray, o:int, l:int):void
this.writeBytes = function(data, o, l) {
var
nalUnitSize, // :uint
s, // :uint
e, // :uint
t; // :int
if (l <= 0) {
// data is empty so there's nothing to write
return;
}
// scan through the bytes until we find the start code (0x000001) for a
// NAL unit and then begin writing it out
switch (state) {
default:
/* falls through */
case 0:
state = 1;
/* falls through */
case 1:
// A NAL unit may be split across two TS packets. Look back a bit to
// make sure the prefix of the start code wasn't already written out.
if (data[o] <= 1) {
nalUnitSize = h264Frame ? h264Frame.nalUnitSize() : 0;
if (nalUnitSize >= 1 && h264Frame.negIndex(1) === 0) {
// ?? ?? 00 | O[01] ?? ??
if (1 === data[o] && 2 <= nalUnitSize && 0 === h264Frame.negIndex(2)) {
// ?? 00 00 : 01
if (3 <= nalUnitSize && 0 === h264Frame.negIndex(3)) {
h264Frame.length -= 3; // 00 00 00 : 01
} else {
h264Frame.length -= 2; // 00 00 : 01
}
state = 3;
return this.writeBytes(data, o + 1, l - 1);
}
if (1 < l && 0 === data[o] && 1 === data[o + 1]) {
// ?? 00 | 00 01
if (2 <= nalUnitSize && 0 === h264Frame.negIndex(2)) {
h264Frame.length -= 2; // 00 00 : 00 01
} else {
h264Frame.length -= 1; // 00 : 00 01
}
state = 3;
return this.writeBytes(data, o + 2, l - 2);
}
if (2 < l && 0 === data[o] && 0 === data[o + 1] && 1 === data[o + 2]) {
// 00 | 00 00 01
h264Frame.length -= 1;
state = 3;
return this.writeBytes(data, o + 3, l - 3);
}
}
}
// allow fall through if the above fails, we may end up checking a few
// bytes a second time. But that case will be VERY rare
state = 2;
/* falls through */
case 2: // Look for start codes in data
s = o; // s = Start
e = s + l; // e = End
for (t = e - 3 ; o < t ;) {
if (1 < data[o + 2]) {
o += 3; // if data[o + 2] is greater than 1, there is no way a start code can begin before o+3
} else if (0 !== data[o + 1]) {
o += 2;
} else if (0 !== data[o]) {
o += 1;
} else {
// If we get here we have 00 00 00 or 00 00 01
if (1 === data[o + 2]) {
if (o > s) {
h264Frame.writeBytes(data, s, o - s);
}
state = 3;
o += 3;
return this.writeBytes(data, o, e - o);
}
if (e - o >= 4 && 0 === data[o + 2] && 1 === data[o + 3]) {
if (o > s) {
h264Frame.writeBytes(data, s, o - s);
}
state = 3;
o += 4;
return this.writeBytes(data, o, e - o);
}
// We are at the end of the buffer, or we have 3 NULLS followed by
// something that is not a 1, either way we can step forward by at
// least 3
o += 3;
}
}
// We did not find any start codes. Try again next packet
state = 1;
h264Frame.writeBytes(data, s, l);
return;
case 3:
// The next byte is the first byte of a NAL Unit
if (h264Frame) {
// we've come to a new NAL unit so finish up the one we've been
// working on
switch (nalUnitType) {
case NALUnitType.seq_parameter_set_rbsp:
h264Frame.endNalUnit(newExtraData.sps);
break;
case NALUnitType.pic_parameter_set_rbsp:
h264Frame.endNalUnit(newExtraData.pps);
break;
case NALUnitType.slice_layer_without_partitioning_rbsp_idr:
h264Frame.keyFrame = true;
h264Frame.endNalUnit();
break;
default:
h264Frame.endNalUnit();
break;
}
}
// setup to begin processing the new NAL unit
nalUnitType = data[o] & 0x1F;
if (h264Frame && 9 === nalUnitType) {
this.finishFrame(); // We are starting a new access unit. Flush the previous one
}
// finishFrame may render h264Frame null, so we must test again
if (!h264Frame) {
h264Frame = new FlvTag(FlvTag.VIDEO_TAG);
h264Frame.pts = next_pts;
h264Frame.dts = next_dts;
}
h264Frame.startNalUnit();
state = 2; // We know there will not be an overlapping start code, so we can skip that test
return this.writeBytes(data, o, l);
/*--------------------------------------------------------------------------------------------------------------------*/
} // switch
};
};
})(this);