yv12、I420、nv12、nv21相互转换
YUV420P，Y，U，V三个分量都是平面格式，分为I420和YV12。I420格式和YV12格式的不同处在U平面和V平面的位置不同。在I420格式中，U平面紧跟在Y平面之后，然后才是V平面（即：YUV）；但YV12则是相反（即：YVU）。
YUV420SP, Y分量平面格式，UV打包格式, 即NV12。 NV12与NV21类似，U 和 V 交错排列,不同在于UV顺序。
I420: YYYYYYYY UU VV =>YUV420P
YV12: YYYYYYYY VV UU =>YUV420P
NV12: YYYYYYYY UVUV =>YUV420SP
NV21: YYYYYYYY VUVU =>YUV420SP
1、
NV21
转
nv12
private void
swapNV21ToNV12(
byte
[] nv21,
byte
[] nv12,
int
width,
int
height){
if
(nv21 ==
null
|| nv12 ==
null
)
return
;
int
framesize = width*height;
int
i =
0
,j =
0
;
System.
arraycopy
(nv21,
0
, nv12,
0
, framesize);
for
(j =
0
; j < framesize/
2
; j+=
2
)
{
nv12[framesize + j +
1
] = nv21[j + framesize];
}
for
(j =
0
; j < framesize/
2
; j +=
2
)
{
nv12[framesize + j] = nv21[j + framesize +
1
];
}
}
2、YV12转I420
private void
swapYV12toI420(
byte
[] yv12bytes,
byte
[] i420bytes,
int
width
,
int
height)
{
System.
arraycopy
(yv12bytes,
0
, i420bytes,
0
,
width
*height);
System.
arraycopy
(yv12bytes,
width
*height+
width
*height/
4
, i420bytes,
width
*height,
width
*height/
4
);
System.
arraycopy
(yv12bytes,
width
*height, i420bytes,
width
*height+
width
*height/
4
,
width
*height/
4
);
}
3、yv12转nv12
void
swapYV12toNV12(
byte
[] yv12bytes,
byte
[] nv12bytes,
int
width,
int
height)
{
int
nLenY = width * height;
int
nLenU = nLenY /
4
;
System.
arraycopy
(yv12bytes,
0
, nv12bytes,
0
, width * height);
for
(
int
i =
0
; i < nLenU; i++) {
nv12bytes[nLenY +
2
* i +
1
] = yv12bytes[nLenY + i];
nv12bytes[nLenY +
2
* i] = yv12bytes[nLenY + nLenU + i];
}
}
4、nv12转I420
void swapNV12toI420(byte[] nv12bytes, byte[] i420bytes, int width,int height)
{
int nLenY = width * height;
int nLenU = nLenY / 4;
System.arraycopy(nv12bytes, 0, i420bytes, 0, width * height);
for (int i = 0; i < nLenU; i++) {
i420bytes[nLenY + i] = nv12bytes[nLenY + 2 * i + 1];
i420bytes[nLenY + nLenU + i] = nv12bytes[nLenY + 2 * i];
}