Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

jpeg, mjpeg: Minor improvements to encoding #135

Merged
merged 1 commit into from
Nov 4, 2021
Merged

jpeg, mjpeg: Minor improvements to encoding #135

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
32 changes: 6 additions & 26 deletions encoder/mjpeg_encoder.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -70,40 +70,20 @@ void MjpegEncoder::encodeJPEG(struct jpeg_compress_struct &cinfo, EncodeItem &it
uint8_t *Y = (uint8_t *)item.mem;
uint8_t *U = (uint8_t *)Y + item.stride * item.height;
uint8_t *V = (uint8_t *)U + stride2 * (item.height / 2);
uint8_t *Y_max = U - item.stride;
uint8_t *U_max = V - stride2;
uint8_t *V_max = U_max + stride2 * (item.height / 2);

JSAMPROW y_rows[16];
JSAMPROW u_rows[8];
JSAMPROW v_rows[8];

unsigned int height_align = item.height & ~15;
while (cinfo.next_scanline < height_align)
for (uint8_t *Y_row = Y, *U_row = U, *V_row = V; cinfo.next_scanline < item.height;)
{
uint8_t *Y_row = Y + cinfo.next_scanline * item.stride;
for (int i = 0; i < 16; i++, Y_row += item.stride)
y_rows[i] = Y_row;
uint8_t *U_row = U + (cinfo.next_scanline / 2) * stride2;
uint8_t *V_row = V + (cinfo.next_scanline / 2) * stride2;
y_rows[i] = std::min(Y_row, Y_max);
for (int i = 0; i < 8; i++, U_row += stride2, V_row += stride2)
u_rows[i] = U_row, v_rows[i] = V_row;

JSAMPARRAY rows[] = { y_rows, u_rows, v_rows };
jpeg_write_raw_data(&cinfo, rows, 16);
}
if (cinfo.next_scanline < item.height)
{
// Raw data has to be written in blocks of 16 rows, so rows beyond the highest
// multiple of 16 have to be copied to a 16-row sized buffer and then added.
std::vector<uint8_t> y_pixels(16 * item.stride);
std::vector<uint8_t> u_pixels(8 * stride2);
std::vector<uint8_t> v_pixels(8 * stride2);
memcpy(&y_pixels[0], Y + height_align * item.stride, (item.height & 15) * item.stride);
memcpy(&u_pixels[1], U + height_align / 2 * stride2, (item.height & 15) / 2 * stride2);
memcpy(&v_pixels[1], V + height_align / 2 * stride2, (item.height & 15) / 2 * stride2);

for (int i = 0; i < 16; i++)
y_rows[i] = &y_pixels[i * item.stride];
for (int i = 0; i < 8; i++)
u_rows[i] = &u_pixels[i * stride2], v_rows[i] = &v_pixels[i * stride2];
u_rows[i] = std::min(U_row, U_max), v_rows[i] = std::min(V_row, V_max);

JSAMPARRAY rows[] = { y_rows, u_rows, v_rows };
jpeg_write_raw_data(&cinfo, rows, 16);
Expand Down
32 changes: 6 additions & 26 deletions image/jpeg.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -332,40 +332,20 @@ static void YUV420_to_JPEG_fast(const uint8_t *input, const unsigned int width,
uint8_t *Y = (uint8_t *)input;
uint8_t *U = (uint8_t *)Y + stride * height;
uint8_t *V = (uint8_t *)U + stride2 * (height / 2);
uint8_t *Y_max = U - stride;
uint8_t *U_max = V - stride2;
uint8_t *V_max = U_max + stride2 * (height / 2);

JSAMPROW y_rows[16];
JSAMPROW u_rows[8];
JSAMPROW v_rows[8];

unsigned int height_align = height & ~15;
while (cinfo.next_scanline < height_align)
for (uint8_t *Y_row = Y, *U_row = U, *V_row = V; cinfo.next_scanline < height;)
{
uint8_t *Y_row = Y + cinfo.next_scanline * stride;
for (int i = 0; i < 16; i++, Y_row += stride)
y_rows[i] = Y_row;
uint8_t *U_row = U + (cinfo.next_scanline / 2) * stride2;
uint8_t *V_row = V + (cinfo.next_scanline / 2) * stride2;
y_rows[i] = std::min(Y_row, Y_max);
for (int i = 0; i < 8; i++, U_row += stride2, V_row += stride2)
u_rows[i] = U_row, v_rows[i] = V_row;

JSAMPARRAY rows[] = { y_rows, u_rows, v_rows };
jpeg_write_raw_data(&cinfo, rows, 16);
}
if (cinfo.next_scanline < height)
{
// Raw data has to be written in blocks of 16 rows, so rows beyond the highest
// multiple of 16 have to be copied to a 16-row sized buffer and then added.
std::vector<uint8_t> y_pixels(16 * stride);
std::vector<uint8_t> u_pixels(8 * stride2);
std::vector<uint8_t> v_pixels(8 * stride2);
memcpy(&y_pixels[0], Y + height_align * stride, (height & 15) * stride);
memcpy(&u_pixels[1], U + height_align / 2 * stride2, (height & 15) / 2 * stride2);
memcpy(&v_pixels[1], V + height_align / 2 * stride2, (height & 15) / 2 * stride2);

for (int i = 0; i < 16; i++)
y_rows[i] = &y_pixels[i * stride];
for (int i = 0; i < 8; i++)
u_rows[i] = &u_pixels[i * stride2], v_rows[i] = &v_pixels[i * stride2];
u_rows[i] = std::min(U_row, U_max), v_rows[i] = std::min(V_row, V_max);

JSAMPARRAY rows[] = { y_rows, u_rows, v_rows };
jpeg_write_raw_data(&cinfo, rows, 16);
Expand Down