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Fix support for y4m color spaces #629

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Fix support for y4m color spaces #629

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f7a6683
Fix support for y4m color spaces
chemag May 26, 2025
63a91b0
Fix support for y4m files with odd dimensions
chemag Jun 2, 2025
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137 changes: 95 additions & 42 deletions YUViewLib/src/playlistitem/playlistItemRawFile.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -320,50 +320,101 @@ bool playlistItemRawFile::parseY4MFile()
}
else if (parameterIndicator == 'C')
{
// Get 3 bytes and check them
auto formatName = rawData.mid(offset, 3);
offset += 3;

// The YUV format. By default, YUV420 is setup.
// TDOO: What is the difference between these two formats?
// 'C420' = 4:2:0 with coincident chroma planes
// 'C420jpeg' = 4:2 : 0 with biaxially - displaced chroma planes
// 'C420paldv' = 4 : 2 : 0 with vertically - displaced chroma planes
// get the full word
int space_index = rawData.indexOf(' ', offset);
auto formatName = rawData.mid(offset, space_index - offset);
offset = space_index;
unsigned bitsPerSample = 8;
auto subsampling = video::yuv::Subsampling::YUV_420;
if (formatName == "422")
if ((formatName == "420") ||
// 'C420' = 4:2:0 with coincident chroma planes
(formatName == "420jpeg") ||
// 'C420jpeg' = 4:2 : 0 with biaxially - displaced chroma planes
(formatName == "420mpeg2") ||
(formatName == "420paldv")) {
// 'C420paldv' = 4 : 2 : 0 with vertically - displaced chroma planes
bitsPerSample = 8;
subsampling = video::yuv::Subsampling::YUV_420;

} else if (formatName == "422") {
bitsPerSample = 8;
subsampling = video::yuv::Subsampling::YUV_422;
else if (formatName == "444")

} else if (formatName == "444") {
bitsPerSample = 8;
subsampling = video::yuv::Subsampling::YUV_444;

unsigned bitsPerSample = 8;
} else if (formatName == "mono") {
bitsPerSample = 8;
subsampling = video::yuv::Subsampling::YUV_400;

if (rawData.at(offset) == 'p')
{
offset++;
if (rawData.at(offset) == '1')
{
offset++;
if (rawData.at(offset) == '0')
{
bitsPerSample = 10;
offset++;
}
else if (rawData.at(offset) == '2')
{
bitsPerSample = 12;
offset++;
}
else if (rawData.at(offset) == '4')
{
bitsPerSample = 14;
offset++;
}
else if (rawData.at(offset) == '6')
{
bitsPerSample = 16;
offset++;
}
}
} else if (formatName == "411") {
bitsPerSample = 8;
subsampling = video::yuv::Subsampling::YUV_411;

// 10-bit components
} else if (formatName == "420p10") {
bitsPerSample = 10;
subsampling = video::yuv::Subsampling::YUV_420;

} else if (formatName == "422p10") {
bitsPerSample = 10;
subsampling = video::yuv::Subsampling::YUV_422;

} else if (formatName == "444p10") {
bitsPerSample = 10;
subsampling = video::yuv::Subsampling::YUV_444;

} else if (formatName == "mono10") {
bitsPerSample = 10;
subsampling = video::yuv::Subsampling::YUV_400;

// 12-bit components
} else if (formatName == "420p12") {
bitsPerSample = 12;
subsampling = video::yuv::Subsampling::YUV_420;

} else if (formatName == "422p12") {
bitsPerSample = 12;
subsampling = video::yuv::Subsampling::YUV_422;

} else if (formatName == "444p12") {
bitsPerSample = 12;
subsampling = video::yuv::Subsampling::YUV_444;

} else if (formatName == "mono12") {
bitsPerSample = 12;
subsampling = video::yuv::Subsampling::YUV_400;

// 14-bit components
} else if (formatName == "420p14") {
bitsPerSample = 14;
subsampling = video::yuv::Subsampling::YUV_420;

} else if (formatName == "422p14") {
bitsPerSample = 14;
subsampling = video::yuv::Subsampling::YUV_422;

} else if (formatName == "444p14") {
bitsPerSample = 14;
subsampling = video::yuv::Subsampling::YUV_444;

// 16-bit components
} else if (formatName == "420p16") {
bitsPerSample = 16;
subsampling = video::yuv::Subsampling::YUV_420;

} else if (formatName == "422p16") {
bitsPerSample = 16;
subsampling = video::yuv::Subsampling::YUV_422;

} else if (formatName == "444p16") {
bitsPerSample = 16;
subsampling = video::yuv::Subsampling::YUV_444;

} else if (formatName == "mono16") {
bitsPerSample = 16;
subsampling = video::yuv::Subsampling::YUV_400;
}

format = video::yuv::PixelFormatYUV(subsampling, bitsPerSample);
Expand Down Expand Up @@ -396,11 +447,13 @@ bool playlistItemRawFile::parseY4MFile()
// parameters is also terminated by 0x0A.

// The offset in bytes to the next frame
auto stride = width * height * 3 / 2;
auto ypixels = width * height;
auto cpixels = ((width + 1) / 2) * ((height + 1) / 2);
if (format.getSubsampling() == video::yuv::Subsampling::YUV_422)
stride = width * height * 2;
cpixels = ((width + 1) / 2) * height;
else if (format.getSubsampling() == video::yuv::Subsampling::YUV_444)
stride = width * height * 3;
cpixels = width * height;
auto stride = ypixels + 2 * cpixels;
if (format.getBitsPerSample() > 8)
stride *= 2;

Expand Down