DirectShowPixelFormat.hpp File Reference

DirectShow / Video-for-Windows fourcc <-> Video::VideoPixelFormat. More...

Detailed Description

DirectShow / Video-for-Windows fourcc <-> Video::VideoPixelFormat.

The YUV MEDIASUBTYPE_* GUIDs are all of the form {fourcc, 0x0000, 0x0010, {0x80,0x00,0x00,0xaa,0x00,0x38,0x9b,0x71}}, so the subtype reduces to the fourcc in Data1. Keeping the table in those terms makes it portable and unit-testable on any host, instead of hiding a mapping nobody can exercise inside Windows-only code. The RGB subtypes are genuine SDK GUIDs rather than fourccs and stay with the DirectShow enumeration.

Deliberately not platform-guarded: the point is that it builds and is tested everywhere.

Go to the source code of this file.

Namespaces
namespace	score
	Base toolkit upon which the software is built.
namespace	score::gfx
	Graphics rendering pipeline for ossia score.

Functions
constexpr uint32_t	score::gfx::interop::directShowFourcc (char a, char b, char c, char d) noexcept
	Build a fourcc the way DirectShow spells it, least-significant byte first.
Video::VideoPixelFormat	score::gfx::interop::fromDirectShowFourcc (uint32_t fourcc) noexcept
AVCodecID	score::gfx::interop::directShowFourccCodec (uint32_t fourcc) noexcept
bool	score::gfx::interop::isDirectShowCompressedFourcc (uint32_t fourcc) noexcept

Function Documentation

directShowFourccCodec()

AVCodecID score::gfx::interop::directShowFourccCodec ( uint32_t  fourcc )

noexcept

What decodes a DirectShow fourcc: AV_CODEC_ID_RAWVIDEO when fromDirectShowFourcc names its layout, a decoder when the stream is compressed, AV_CODEC_ID_NONE when neither — an unsupported subtype.

The compressed half comes from FFmpeg's RIFF video tags, so it covers every spelling FFmpeg knows; only what that table lacks and DirectShow emits (H.265, the odd Motion-JPEG fourccs, MDVF) is listed here.

fromDirectShowFourcc()

Video::VideoPixelFormat score::gfx::interop::fromDirectShowFourcc ( uint32_t  fourcc )

noexcept

The layout behind a DirectShow YUV fourcc, or Unknown for compressed, RGB-GUID and unhandled subtypes.

isDirectShowCompressedFourcc()

bool score::gfx::interop::isDirectShowCompressedFourcc ( uint32_t  fourcc )

noexcept

True when the fourcc names a compressed stream rather than a raw layout, so the caller reaches for a decoder instead of a pixel format.