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h264_metadata_bsf: Improve interpretation of input display matrices

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The previous code here only worked in more limited cases.
This commit is contained in:
Mark Thompson 2021-01-01 21:35:16 +00:00
parent 8a14d51b8b
commit c9c5b1977f
1 changed files with 30 additions and 14 deletions
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44
libavcodec/h264_metadata_bsf.c
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@ -431,23 +431,39 @@ static int h264_metadata_handle_display_orientation(AVBSFContext *bsf,
data = av_packet_get_side_data(pkt, AV_PKT_DATA_DISPLAYMATRIX, &size);
if (data && size >= 9 * sizeof(int32_t)) {
int32_t matrix[9];
int hflip, vflip;
double angle;
double dmatrix[9];
int hflip, vflip, i;
double scale_x, scale_y, angle;
memcpy(matrix, data, sizeof(matrix));
hflip = vflip = 0;
if (matrix[0] < 0 && matrix[4] > 0)
hflip = 1;
else if (matrix[0] > 0 && matrix[4] < 0)
vflip = 1;
av_display_matrix_flip(matrix, hflip, vflip);
for (i = 0; i < 9; i++)
dmatrix[i] = matrix[i] / 65536.0;
angle = av_display_rotation_get(matrix);
// Extract scale factors.
scale_x = hypot(dmatrix[0], dmatrix[3]);
scale_y = hypot(dmatrix[1], dmatrix[4]);
if (!(angle >= -180.0 && angle <= 180.0 /* also excludes NaN */) ||
matrix[2] != 0 || matrix[5] != 0 ||
matrix[6] != 0 || matrix[7] != 0) {
// Select flips to make the main diagonal positive.
hflip = dmatrix[0] < 0.0;
vflip = dmatrix[4] < 0.0;
if (hflip)
scale_x = -scale_x;
if (vflip)
scale_y = -scale_y;
// Rescale.
for (i = 0; i < 9; i += 3) {
dmatrix[i] /= scale_x;
dmatrix[i + 1] /= scale_y;
}
// Extract rotation.
angle = atan2(dmatrix[3], dmatrix[0]);
if (!(angle >= -M_PI && angle <= M_PI) ||
matrix[2] != 0.0 || matrix[5] != 0.0 ||
matrix[6] != 0.0 || matrix[7] != 0.0) {
av_log(bsf, AV_LOG_WARNING, "Input display matrix is not "
"representable in H.264 parameters.\n");
} else {
@ -455,8 +471,8 @@ static int h264_metadata_handle_display_orientation(AVBSFContext *bsf,
disp->ver_flip = vflip;
disp->anticlockwise_rotation =
(uint16_t)rint((angle >= 0.0 ? angle
: angle + 360.0) *
65536.0 / 360.0);
: angle + 2 * M_PI) *
32768.0 / M_PI);
write = 1;
}
}