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BGRA RTCCVPixelBuffers were cropped and scaled incorrectly. Libyuv’s `ARGBScale` method is used in RTCCVPixelBuffer to scale and crop the pixel buffer. To crop by `cropX` and `cropY` pixels, pointer arithmetic is used to offset the src pointer of the original pixel buffer bytes. There is a bug in how this offset is calculated. The offset is done by `src += srcStride * _cropY + _cropX`. Libyuv expects that the src pointer will point to the start of a new pixel. However, if _cropX is a not a multiple of 4 (4 bytes for BGRA), the src pointer will point to a byte in the middle of a pixel and thus libyuv will incorrectly treat the data as the start of pixel (incorrectly treating the first byte as red when it is actually green, etc...). To fix this, the src pointer needs to be offset to always point to the start of a new pixel. Before this change: Original Test Gradient image with a cropX of 2: https://i.imgur.com/gSIgwGV.jpg Scaled image (notice the colors are incorrect): https://i.imgur.com/oPxbTEK.jpg After this change: Scaled image (notice the colors are correct): https://i.imgur.com/dqBsmsH.jpg A new unit test which tests scaling with cropX and cropY values has been added. The test fails without this change and now passes with the correct src pointer offsetting. Bug: webrtc:9555 Change-Id: I87cbd7b91bc139d51fb4e11cc50ccb014cfa8051 Reviewed-on: https://webrtc-review.googlesource.com/89220 Commit-Queue: Kári Helgason <kthelgason@webrtc.org> Reviewed-by: Kári Helgason <kthelgason@webrtc.org> Cr-Commit-Position: refs/heads/master@{#24076} |
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| .. | ||
| AVCaptureSession+DevicePosition.h | ||
| AVCaptureSession+DevicePosition.mm | ||
| RTCCVPixelBuffer.mm | ||
| RTCDefaultShader.h | ||
| RTCDefaultShader.mm | ||
| RTCI420Buffer+Private.h | ||
| RTCI420Buffer.mm | ||
| RTCI420TextureCache.h | ||
| RTCI420TextureCache.mm | ||
| RTCNV12TextureCache.h | ||
| RTCNV12TextureCache.m | ||
| RTCOpenGLDefines.h | ||
| RTCShader.h | ||
| RTCShader.mm | ||
| UIDevice+H264Profile.h | ||
| UIDevice+H264Profile.mm | ||
