Recently I've been trying to play some AV1-encoded streams on my iPhone 15 Pro Max. First, I check for hardware support:
VTIsHardwareDecodeSupported(kCMVideoCodecType_AV1); // YES
Then I need to create a CMFormatDescription in order to pass it into a VTDecompressionSession. I've tried the following:
{
mediaType:'vide'
mediaSubType:'av01'
mediaSpecific: {
codecType: 'av01' dimensions: 394 x 852
}
extensions: {{
CVFieldCount = 1;
CVImageBufferChromaLocationBottomField = Left;
CVImageBufferChromaLocationTopField = Left;
CVPixelAspectRatio = {
HorizontalSpacing = 1;
VerticalSpacing = 1;
};
FullRangeVideo = 0;
}}
}
but VTDecompressionSessionCreate gives me error -8971 (codecExtensionNotFoundErr, I assume).
So it has something to do with the extensions dictionary? I can't find anywhere which set of extensions is necessary for it to work 😿.
VideoToolbox has convenient functions for creating descriptions of AVC and HEVC streams (CMVideoFormatDescriptionCreateFromH264ParameterSets and CMVideoFormatDescriptionCreateFromHEVCParameterSets), but not for AV1.
As of today I am using XCode 15.0 with iOS 17.0.0 SDK.
mrlvsva
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