shaka-player
Version:
DASH/EME video player library
426 lines (380 loc) • 13 kB
JavaScript
/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.transmuxer.H264');
goog.require('shaka.util.ExpGolomb');
goog.require('shaka.util.Uint8ArrayUtils');
/**
* H.264 utils
*/
shaka.transmuxer.H264 = class {
/**
* Read a sequence parameter set and return some interesting video
* properties. A sequence parameter set is the H264 metadata that
* describes the properties of upcoming video frames.
*
* @param {!Array<shaka.extern.VideoNalu>} nalus
* @return {?{height: number, width: number, videoConfig: !Uint8Array,
* hSpacing: number, vSpacing: number}}
*/
static parseInfo(nalus) {
const H264 = shaka.transmuxer.H264;
if (!nalus.length) {
return null;
}
const spsNalu = nalus.find((nalu) => {
return nalu.type == H264.NALU_TYPE_SPS_;
});
const ppsNalu = nalus.find((nalu) => {
return nalu.type == H264.NALU_TYPE_PPS_;
});
if (!spsNalu || !ppsNalu) {
return null;
}
const expGolombDecoder = new shaka.util.ExpGolomb(spsNalu.data);
// profile_idc
const profileIdc = expGolombDecoder.readUnsignedByte();
// constraint_set[0-5]_flag
expGolombDecoder.readUnsignedByte();
// level_idc u(8)
expGolombDecoder.readUnsignedByte();
// seq_parameter_set_id
expGolombDecoder.skipExpGolomb();
// some profiles have more optional data we don't need
if (H264.PROFILES_WITH_OPTIONAL_SPS_DATA_.includes(profileIdc)) {
const chromaFormatIdc = expGolombDecoder.readUnsignedExpGolomb();
if (chromaFormatIdc === 3) {
// separate_colour_plane_flag
expGolombDecoder.skipBits(1);
}
// bit_depth_luma_minus8
expGolombDecoder.skipExpGolomb();
// bit_depth_chroma_minus8
expGolombDecoder.skipExpGolomb();
// qpprime_y_zero_transform_bypass_flag
expGolombDecoder.skipBits(1);
// seq_scaling_matrix_present_flag
if (expGolombDecoder.readBoolean()) {
const scalingListCount = (chromaFormatIdc !== 3) ? 8 : 12;
for (let i = 0; i < scalingListCount; i++) {
// seq_scaling_list_present_flag[ i ]
if (expGolombDecoder.readBoolean()) {
if (i < 6) {
expGolombDecoder.skipScalingList(16);
} else {
expGolombDecoder.skipScalingList(64);
}
}
}
}
}
// log2_max_frame_num_minus4
expGolombDecoder.skipExpGolomb();
const picOrderCntType = expGolombDecoder.readUnsignedExpGolomb();
if (picOrderCntType === 0) {
// log2_max_pic_order_cnt_lsb_minus4
expGolombDecoder.readUnsignedExpGolomb();
} else if (picOrderCntType === 1) {
// delta_pic_order_always_zero_flag
expGolombDecoder.skipBits(1);
// offset_for_non_ref_pic
expGolombDecoder.skipExpGolomb();
// offset_for_top_to_bottom_field
expGolombDecoder.skipExpGolomb();
const numRefFramesInPicOrderCntCycle =
expGolombDecoder.readUnsignedExpGolomb();
for (let i = 0; i < numRefFramesInPicOrderCntCycle; i++) {
// offset_for_ref_frame[ i ]
expGolombDecoder.skipExpGolomb();
}
}
// max_num_ref_frames
expGolombDecoder.skipExpGolomb();
// gaps_in_frame_num_value_allowed_flag
expGolombDecoder.skipBits(1);
const picWidthInMbsMinus1 =
expGolombDecoder.readUnsignedExpGolomb();
const picHeightInMapUnitsMinus1 =
expGolombDecoder.readUnsignedExpGolomb();
const frameMbsOnlyFlag = expGolombDecoder.readBits(1);
if (frameMbsOnlyFlag === 0) {
// mb_adaptive_frame_field_flag
expGolombDecoder.skipBits(1);
}
// direct_8x8_inference_flag
expGolombDecoder.skipBits(1);
let frameCropLeftOffset = 0;
let frameCropRightOffset = 0;
let frameCropTopOffset = 0;
let frameCropBottomOffset = 0;
// frame_cropping_flag
if (expGolombDecoder.readBoolean()) {
frameCropLeftOffset = expGolombDecoder.readUnsignedExpGolomb();
frameCropRightOffset = expGolombDecoder.readUnsignedExpGolomb();
frameCropTopOffset = expGolombDecoder.readUnsignedExpGolomb();
frameCropBottomOffset = expGolombDecoder.readUnsignedExpGolomb();
}
let hSpacing = 1;
let vSpacing = 1;
// vui_parameters_present_flag
if (expGolombDecoder.readBoolean()) {
// aspect_ratio_info_present_flag
if (expGolombDecoder.readBoolean()) {
const aspectRatioIdc = expGolombDecoder.readUnsignedByte();
const hSpacingTable = [
1, 12, 10, 16, 40, 24, 20, 32, 80, 18, 15, 64, 160, 4, 3, 2,
];
const vSpacingTable = [
1, 11, 11, 11, 33, 11, 11, 11, 33, 11, 11, 33, 99, 3, 2, 1,
];
if (aspectRatioIdc > 0 && aspectRatioIdc <= 16) {
hSpacing = hSpacingTable[aspectRatioIdc - 1];
vSpacing = vSpacingTable[aspectRatioIdc - 1];
} else if (aspectRatioIdc === 255) {
hSpacing = expGolombDecoder.readBits(16);
vSpacing = expGolombDecoder.readBits(16);
}
}
}
const height = ((2 - frameMbsOnlyFlag) *
(picHeightInMapUnitsMinus1 + 1) * 16) - (frameCropTopOffset * 2) -
(frameCropBottomOffset * 2);
const width = ((picWidthInMbsMinus1 + 1) * 16) -
frameCropLeftOffset * 2 - frameCropRightOffset * 2;
// assemble the SPSs
let sps = [];
const spsData = spsNalu.fullData;
sps.push((spsData.byteLength >>> 8) & 0xff);
sps.push(spsData.byteLength & 0xff);
sps = sps.concat(...spsData);
// assemble the PPSs
let pps = [];
const ppsData = ppsNalu.fullData;
pps.push((ppsData.byteLength >>> 8) & 0xff);
pps.push(ppsData.byteLength & 0xff);
pps = pps.concat(...ppsData);
const videoConfig = new Uint8Array(
[
0x01, // version
sps[3], // profile
sps[4], // profile compat
sps[5], // level
0xfc | 3, // lengthSizeMinusOne, hard-coded to 4 bytes
0xe0 | 1, // 3bit reserved (111) + numOfSequenceParameterSets
].concat(sps).concat([
1, // numOfPictureParameterSets
]).concat(pps));
return {
height,
width,
videoConfig,
hSpacing,
vSpacing,
};
}
/**
* @param {!Array<shaka.extern.MPEG_PES>} videoData
* @return {!Array<shaka.extern.VideoSample>}
*/
static getVideoSamples(videoData) {
const H264 = shaka.transmuxer.H264;
/** @type {!Array<shaka.extern.VideoSample>} */
const videoSamples = [];
/** @type {?shaka.extern.VideoSample} */
let lastVideoSample = null;
/** @type {boolean} */
let audFound = false;
const addLastVideoSample = () => {
if (!lastVideoSample) {
return;
}
if (!lastVideoSample.nalus.length || !lastVideoSample.frame) {
return;
}
const nalusData = [];
for (const nalu of lastVideoSample.nalus) {
const size = nalu.fullData.byteLength;
const naluLength = new Uint8Array(4);
naluLength[0] = (size >> 24) & 0xff;
naluLength[1] = (size >> 16) & 0xff;
naluLength[2] = (size >> 8) & 0xff;
naluLength[3] = size & 0xff;
nalusData.push(naluLength);
nalusData.push(nalu.fullData);
}
lastVideoSample.data = shaka.util.Uint8ArrayUtils.concat(...nalusData);
videoSamples.push(lastVideoSample);
};
const createLastVideoSample = (pes) => {
lastVideoSample = {
data: new Uint8Array([]),
frame: false,
isKeyframe: false,
pts: pes.pts,
dts: pes.dts,
nalus: [],
};
};
for (let i = 0; i < videoData.length; i++) {
const pes = videoData[i];
const nalus = pes.nalus;
let spsFound = false;
// If new NAL units found and last sample still there, let's push ...
// This helps parsing streams with missing AUD
// (only do this if AUD never found)
if (lastVideoSample && nalus.length && !audFound) {
addLastVideoSample();
createLastVideoSample(pes);
}
for (const nalu of pes.nalus) {
let push = false;
switch (nalu.type) {
case H264.NALU_TYPE_NDR_: {
let isKeyframe = false;
push = true;
const data = nalu.data;
// Only check slice type to detect KF in case SPS found in same
// packet (any keyframe is preceded by SPS ...)
if (spsFound && data.length > 4) {
// retrieve slice type by parsing beginning of NAL unit (follow
// H264 spec,slice_header definition) to detect keyframe embedded
// in NDR
const sliceType = new shaka.util.ExpGolomb(data).readSliceType();
// 2 : I slice, 4 : SI slice, 7 : I slice, 9: SI slice
// SI slice : A slice that is coded using intra prediction only
// and using quantisation of the prediction samples.
// An SI slice can be coded such that its decoded samples can be
// constructed identically to an SP slice.
// I slice: A slice that is not an SI slice that is decoded using
// intra prediction only.
if (sliceType === 2 || sliceType === 4 ||
sliceType === 7 || sliceType === 9) {
isKeyframe = true;
}
}
if (isKeyframe) {
// If we have non-keyframe data already, that cannot belong to
// the same frame as a keyframe, so force a push
if (lastVideoSample &&
lastVideoSample.frame && !lastVideoSample.isKeyframe) {
addLastVideoSample();
lastVideoSample = null;
}
}
if (!lastVideoSample) {
createLastVideoSample(pes);
}
lastVideoSample.frame = true;
lastVideoSample.isKeyframe = isKeyframe;
break;
}
case H264.NALU_TYPE_IDR_: {
push = true;
// Handle PES not starting with AUD
// If we have frame data already, that cannot belong to the same
// frame, so force a push
if (lastVideoSample &&
lastVideoSample.frame && !lastVideoSample.isKeyframe) {
addLastVideoSample();
lastVideoSample = null;
}
if (!lastVideoSample) {
createLastVideoSample(pes);
}
lastVideoSample.frame = true;
lastVideoSample.isKeyframe = true;
break;
}
case H264.NALU_TYPE_SEI_:
push = true;
break;
case H264.NALU_TYPE_SPS_:
push = true;
spsFound = true;
break;
case H264.NALU_TYPE_PPS_:
push = true;
break;
case H264.NALU_TYPE_AUD_:
push = true;
audFound = true;
if (lastVideoSample && lastVideoSample.frame) {
addLastVideoSample();
lastVideoSample = null;
}
if (!lastVideoSample) {
createLastVideoSample(pes);
}
break;
case H264.NALU_TYPE_FILLER_DATA_:
push = true;
break;
default:
push = false;
break;
}
if (lastVideoSample && push) {
lastVideoSample.nalus.push(nalu);
}
}
}
// If last PES packet, push samples
addLastVideoSample();
return videoSamples;
}
};
/**
* NALU type for NDR for H.264.
* @const {number}
* @private
*/
shaka.transmuxer.H264.NALU_TYPE_NDR_ = 0x01;
/**
* NALU type for Instantaneous Decoder Refresh (IDR) for H.264.
* @const {number}
* @private
*/
shaka.transmuxer.H264.NALU_TYPE_IDR_ = 0x05;
/**
* NALU type for Supplemental Enhancement Information (SEI) for H.264.
* @const {number}
* @private
*/
shaka.transmuxer.H264.NALU_TYPE_SEI_ = 0x06;
/**
* NALU type for Sequence Parameter Set (SPS) for H.264.
* @const {number}
* @private
*/
shaka.transmuxer.H264.NALU_TYPE_SPS_ = 0x07;
/**
* NALU type for Picture Parameter Set (PPS) for H.264.
* @const {number}
* @private
*/
shaka.transmuxer.H264.NALU_TYPE_PPS_ = 0x08;
/**
* NALU type for Access Unit Delimiter (AUD) for H.264.
* @const {number}
* @private
*/
shaka.transmuxer.H264.NALU_TYPE_AUD_ = 0x09;
/**
* NALU type for Filler Data for H.264.
* @const {number}
* @private
*/
shaka.transmuxer.H264.NALU_TYPE_FILLER_DATA_ = 0x0c;
/**
* Values of profile_idc that indicate additional fields are included in the
* SPS.
* see Recommendation ITU-T H.264 (4/2013)
* 7.3.2.1.1 Sequence parameter set data syntax
*
* @const {!Array<number>}
* @private
*/
shaka.transmuxer.H264.PROFILES_WITH_OPTIONAL_SPS_DATA_ =
[100, 110, 122, 244, 44, 83, 86, 118, 128, 138, 139, 134];