Java 解析问题H.264序列参数集数据
我需要解析原始H.264数据中的图像大小。以下测试代码适用于案例I testet,但现在如果“Z0IAIOKQCgDLYC3AQEBpB4kRUA==”失败。结果应该是1280x800,但它给出了640x1616:Java 解析问题H.264序列参数集数据,java,parsing,h.264,Java,Parsing,H.264,我需要解析原始H.264数据中的图像大小。以下测试代码适用于案例I testet,但现在如果“Z0IAIOKQCgDLYC3AQEBpB4kRUA==”失败。结果应该是1280x800,但它给出了640x1616: public static void main(String[] args) { decode(StringUtils.fromBase64("Z0IAKeKQCgDLYC3AQEBpB4kRUA==")); decode(StringUtils.fromBase64
public static void main(String[] args) {
decode(StringUtils.fromBase64("Z0IAKeKQCgDLYC3AQEBpB4kRUA=="));
decode(StringUtils.fromBase64("Z0IAIOKQCgDLYC3AQEBpB4kRUA=="));
decode(StringUtils.fromBase64("Z0IAHuNQFAe2AtwEBAaQeJEV"));
}
static int pos;
static byte[] data;
private static void decode(byte[] data) {
try {
System.out.println();
System.out.println(StringUtils.toHex(data));
System.out.println(StringUtils.toBin(data, 0, data.length, true));
System.out.println();
pos = 0;
T.data = data;
int profile_idc = getU(8);
int constraint_set0_flag = getU(1);
int constraint_set1_flag = getU(1);
int constraint_set2_flag = getU(1);
int constraint_set3_flag = getU(1);
int reserved_zero_4bits = getU(4);
int level_idc = getU(8);
int seq_parameter_set_id = uev();
int log2_max_frame_num_minus4 = uev();
int pict_order_cnt_type = uev();
System.out.println("pict_order_cnt_type=" + pict_order_cnt_type);
if (pict_order_cnt_type == 0) {
uev();
} else if (pict_order_cnt_type == 1) {
getU(1);
sev();
sev();
int n = uev();
System.out.println("n*sev, n=" + n);
for (int i = 0; i < n; i++)
sev();
}
int num_ref_frames = uev();
getU(1);
int pic_width = (uev() + 1) * 16;
int pic_height = (uev() + 1) * 16;
int frame_mbs_only_flag = getU(1);
System.out.println(pic_width + " x " + pic_height);
} catch (Exception e) {
e.printStackTrace(System.out);
}
}
private static int ev(boolean signed) {
int bitcount = 0;
StringBuilder expGolomb = new StringBuilder();
while (getBit() == 0) {
expGolomb.append('0');
bitcount++;
}
expGolomb.append("/1");
int result = 1;
for (int i = 0; i < bitcount; i++) {
int b = getBit();
expGolomb.append(b);
result = result * 2 + b;
}
result--;
if (signed) {
result = (result + 1) / 2 * (result % 2 == 0 ? -1 : 1);
System.out.println("getSe(v) = " + (result) + " " + expGolomb);
} else {
System.out.println("getUe(v) = " + (result) + " " + expGolomb);
}
return result;
}
private static int uev() {
return ev(false);
}
private static int sev() {
return ev(true);
}
private static int getU(int bits) {
int result = 0;
for (int i = 0; i < bits; i++) {
result = result * 2 + getBit();
}
System.out.println("getU(" + bits + ") = " + result);
return result;
}
private static int getBit() {
int mask = 1 << (7 - (pos & 7));
int idx = pos >> 3;
pos++;
return ((data[idx] & mask) == 0) ? 0 : 1;
}
publicstaticvoidmain(字符串[]args){
解码(StringUtils.fromBase64(“Z0IAKeKQCgDLYC3AQEBpB4kRUA=”);
解码(StringUtils.fromBase64(“Z0IAIOKQCgDLYC3AQEBpB4kRUA=”);
解码(StringUtils.fromBase64(“z0iahunqfae2atwebaqejev”);
}
静态int-pos;
静态字节[]数据;
专用静态无效解码(字节[]数据){
试一试{
System.out.println();
System.out.println(StringUtils.toHex(数据));
System.out.println(StringUtils.toBin(data,0,data.length,true));
System.out.println();
pos=0;
T.数据=数据;
int profile_idc=getU(8);
int constraint_set0_flag=getU(1);
int constraint_set1_flag=getU(1);
int constraint_set2_flag=getU(1);
int constraint_set3_flag=getU(1);
int保留的0位=getU(4);
国际水平(国际数据中心)(8),;
int seq_参数_set_id=uev();
int log2_max_frame_num_minus4=uev();
int pict_order_cnt_type=uev();
System.out.println(“pict_order_cnt_type=“+pict_order_cnt_type”);
如果(图像顺序控制类型==0){
uev();
}else if(图像顺序信息类型==1){
格图(1);
sev();
sev();
int n=uev();
System.out.println(“n*sev,n=“+n”);
对于(int i=0;i3;
pos++;
返回((数据[idx]&掩码)==0)?0:1;
}
失败案例的输出:
67420020E2900A00CB602DC040406907891150
01100111 01000010 00000000 00100000 11100010 10010000 00001010 00000000 11001011 01100000 00101101 11000000 01000000 01000000 01101001 00000111 10001001 00010001 01010000
getU(8) = 103
getU(1) = 0
getU(1) = 1
getU(1) = 0
getU(1) = 0
getU(4) = 2 << shouldn't this be 0 ? is same with correct parsing!
getU(8) = 0
getUe(v) = 3 00/100
getUe(v) = 13 000/1110 << log2_max_frame_num_minus4 shall be 0-12, inclusive.
getUe(v) = 4 00/101
pict_order_cnt_type=4 << pic_order_cnt_type shall be 0-2, inclusive.
getUe(v) = 3 00/100
getU(1) = 0
getUe(v) = 39 00000/101000
getUe(v) = 100 000000/1100101
getU(1) = 1
640 x 1616
67420020E2900A00CB602DC0404040406907891150
01100111 01000010 00000000 00100000 11100010 10010000 00001010 00000000 11001011 01100000 00101101 11000000 01000000 01000000 01101001 00000111 10001001 00010001 01010000
格图(8)=103
getU(1)=0
格图(1)=1
getU(1)=0
getU(1)=0
getU(4)=2也许不是您所要求的,但是请查看参考实现,看看它们是如何进行解析的
从下载h.264解析器(从这个线程@doom9)
从下载H.264参考软件
这应该让你开始。BTW比特流在附件中描述。B.在规范中。从ITU下载它如果代码中有错误,应丢弃第一个字节,即NAL单元类型:
67 - NAL unit type ( SPS )
42 - Profile Idc ( Baseline profile in your case )
00 - reserved zero
29 - level ( 41 )
e2 - SPS id ( 0 ), max frame num - 4 ( 0 ), POC type ( 0 ),
90 - uev ( 5 ), num ref frames ( 1 ), u ( 0 )
etc
实际上,您可以使用JCodec类作为现成的SPS解析例程。代码中确实存在一个bug(实际上有三个bug)
- 第一个错误是,第一个字节是NAL头(包含:
禁止位(1bit)、NAL参考位(idc)
(2bit)和NAL单元类型(5bit,值应为7以指示SPS单元)
- 第二个bug是总共有5个
constraint_set#u flag
s,而不是3个(占bug 3中描述的两个位)
- 第三个错误是,在当前规范中,
保留零位的数量是2。我想这在过去可能有所不同,但我不确定
因此,我对decode方法做了一些修改,并提出了适合我的版本(顺便说一句,我的类被称为H264Parser,因此语句H264Parser.data=data;
):
私有静态无效解码(字节[]数据){
试一试{
System.out.println();
System.out.println(StringUtils.toHex(数据));
System.out.println(StringUtils.toBin(data,0,data.length,true));
System.out.println();
pos=0;
H264Parser.data=数据;
int禁止的0位=getU(1);
System.out.println(“禁止零位”+禁止零位);
int nal_ref_idc=getU(2);
int nal_单位类型=getU(5);
System.out.println(“nal\u单元类型(SPS应为7)”+nal\u单元类型);
//NAL_头的末尾
//SPS数据的启动
int profile_idc=getU(8);
int constraint_set0_flag=getU(1);
int constraint_set1_flag=getU(1);
int constraint_set2_flag=getU(1);
int constraint_set3_flag=getU(1);
int constraint_set4_flag=getU(1);
int constraint_set5_flag=getU(1);
//规范的当前版本声明有两个保留位
int reserved_zero_2bits=getU(2);
System.out.println(“保留零位”+保留零位);
国际水平(国际数据中心)(8),;
int seq_参数_set_id=uev();
int log2_max_frame_num_minus4=uev()
private static void decode(byte[] data) {
try {
System.out.println();
System.out.println(StringUtils.toHex(data));
System.out.println(StringUtils.toBin(data, 0, data.length, true));
System.out.println();
pos = 0;
H264Parser.data = data;
int forbidden_zero_bit = getU(1);
System.out.println("forbidden_zero_bit " + forbidden_zero_bit);
int nal_ref_idc = getU(2);
int nal_unit_type = getU(5);
System.out.println("nal_unit_type (should be 7 for SPS) " + nal_unit_type);
//END of NAL_header
//Start of SPS data
int profile_idc = getU(8);
int constraint_set0_flag = getU(1);
int constraint_set1_flag = getU(1);
int constraint_set2_flag = getU(1);
int constraint_set3_flag = getU(1);
int constraint_set4_flag = getU(1);
int constraint_set5_flag = getU(1);
//The current version of the spec states that there are two reserved bits
int reserved_zero_2bits = getU(2);
System.out.println("reserved_zero_2bits" + reserved_zero_2bits);
int level_idc = getU(8);
int seq_parameter_set_id = uev();
int log2_max_frame_num_minus4 = uev();
int pict_order_cnt_type = uev();
System.out.println("pict_order_cnt_type=" + pict_order_cnt_type);
if (pict_order_cnt_type == 0) {
uev();
} else if (pict_order_cnt_type == 1) {
getU(1);
sev();
sev();
int n = uev();
System.out.println("n*sev, n=" + n);
for (int i = 0; i < n; i++)
sev();
}
int num_ref_frames = uev();
getU(1);
int pic_width = (uev() + 1) * 16;
int pic_height = (uev() + 1) * 16;
int frame_mbs_only_flag = getU(1);
System.out.println(pic_width + " x " + pic_height);
} catch (Exception e) {
e.printStackTrace(System.out);
}
}
int seq_parameter_set_id = uev();
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) {
int chroma_format_idc = uev();
if( chroma_format_idc == 3 ){
int separate_colour_plane_flag = getU(1);
}
int bit_depth_luma_minus8 = uev();
int bit_depth_chroma_minus8 = uev();
int qpprime_y_zero_transform_bypass_flag = getU(1);
int seq_scaling_matrix_present_flag = getU(1);
if( seq_scaling_matrix_present_flag == 1) {
int count = (chroma_format_idc != 3) ? 8 : 12;
for (int i = 0; i <count; i++) {
int seq_scaling_list_present_flag_i_ = getU(1);
if (seq_scaling_list_present_flag_i_ == 1) {
if (i < 6)
scaling_list(16);
else
scaling_list(64);
}
}
}
}
int log2_max_frame_num_minus4 = uev();
int[] scaling_list(int sizeOfScalingList){
int lastScale = 8;
int nextScale = 8;
int delta_scale;
boolean useDefaultScalingMatrixFlag;
int[] scalingList = new int[sizeOfScalingList];
for(int j = 0; j < sizeOfScalingList; j++ ) {
if( nextScale != 0 ) {
delta_scale = sev();
nextScale = ( lastScale + delta_scale + 256 ) % 256;
useDefaultScalingMatrixFlag = ( j == 0 && nextScale == 0 );
}
scalingList[ j ] = ( nextScale == 0 ) ? lastScale : nextScale;
lastScale = scalingList[ j ];
}
return scalingList;
}