add experimental NV12 to IYUV conversion routine

This commit is contained in:
Green Sky 2024-10-02 23:35:33 +02:00
parent 2554229211
commit a290bec8f1
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2 changed files with 51 additions and 0 deletions

View File

@ -1,5 +1,7 @@
#include "./video_push_converter.hpp"
#include <cstring>
SDL_Surface* convertYUY2_IYUV(SDL_Surface* surf) {
if (surf->format != SDL_PIXELFORMAT_YUY2) {
return nullptr;
@ -56,3 +58,49 @@ SDL_Surface* convertYUY2_IYUV(SDL_Surface* surf) {
return conv_surf;
}
SDL_Surface* convertNV12_IYUV(SDL_Surface* surf) {
if (surf->format != SDL_PIXELFORMAT_NV12) {
return nullptr;
}
if ((surf->w % 2) != 0) {
SDL_SetError("NV12->IYUV does not support odd widths");
// hmmm, we dont handle odd widths
return nullptr;
}
SDL_LockSurface(surf);
SDL_Surface* conv_surf = SDL_CreateSurface(surf->w, surf->h, SDL_PIXELFORMAT_IYUV);
SDL_LockSurface(conv_surf);
// NV12 is planar Y and interleaved UV in 4:2:0
// Y is simple, we just copy it over
// U V are ... packed?
uint8_t* y_plane = static_cast<uint8_t*>(conv_surf->pixels);
uint8_t* u_plane = static_cast<uint8_t*>(conv_surf->pixels) + conv_surf->w*conv_surf->h;
uint8_t* v_plane = static_cast<uint8_t*>(conv_surf->pixels) + conv_surf->w*conv_surf->h + (conv_surf->w/2)*(conv_surf->h/2);
const uint8_t* nv12_y_plane = static_cast<const uint8_t*>(surf->pixels);
const uint8_t* nv12_uv_data = static_cast<const uint8_t*>(surf->pixels) + surf->w*surf->h;
// y can be copied as is
std::memcpy(
y_plane,
nv12_y_plane,
surf->w*surf->h
);
// we operate at half res
for (int y = 0; y < surf->h/2; y++) {
for (int x = 0; x < surf->w/2; x++) {
u_plane[y*(surf->w/2)+x] = nv12_uv_data[y*(surf->w/2)*2+x*2];
v_plane[y*(surf->w/2)+x] = nv12_uv_data[y*(surf->w/2)*2+x*2+1];
}
}
SDL_UnlockSurface(conv_surf);
SDL_UnlockSurface(surf);
return conv_surf;
}

View File

@ -21,6 +21,7 @@ static bool isFormatYUV(SDL_PixelFormat f) {
}
SDL_Surface* convertYUY2_IYUV(SDL_Surface* surf);
SDL_Surface* convertNV12_IYUV(SDL_Surface* surf);
template<typename RealStream>
struct PushConversionVideoStream : public RealStream {
@ -42,6 +43,8 @@ struct PushConversionVideoStream : public RealStream {
//auto end = Message::getTimeMS();
// 3ms
//std::cerr << "DTC: timing " << SDL_GetPixelFormatName(converted_surf->format) << "->SDL_PIXELFORMAT_IYUV: " << end-start << "ms\n";
} else if (surf->format == SDL_PIXELFORMAT_NV12 && _forced_format == SDL_PIXELFORMAT_IYUV) {
surf = convertNV12_IYUV(surf);
} else if (isFormatYUV(surf->format)) {
// TODO: fix sdl rgb->yuv conversion resulting in too dark (colorspace) issues
// https://github.com/libsdl-org/SDL/issues/10877