Nv12 stride. It is expected to be an intermediate-term requirement for DirectX VA a...

Nv12 stride. It is expected to be an intermediate-term requirement for DirectX VA accelerators supporting 4:2:0 video. 对齐规则对于 NV12 输入，地平线 BPU 要求模型输入 HW 都是偶数，主要是为了满足 UV 是 Y 的一半的要求。有效数据排布和对齐数据排布用 validShape 和 stride 表示。 Jul 14, 2022 · Image Stride指内存中每行像素所占空间，可能大于图像宽度，含扩展字节。处理视频帧转换时需考虑Stride，如YUV420SP转RGB888，需正确偏移地址读取分量，避免图像错乱。本文详细解释了YUV跨距 (Stride)的概念，特别是在处理YUV420P格式图像时的内存对齐需求。通过RGB24和YUV420P格式的对比，说明了如何计算和实现跨距对齐，以及填充字节的作用。 Nov 8, 2024 · src_ 为我们需要转换的NV12格式数据,dst_ 为转换后的i420数据那么stride代表啥??? 跨距-stride 我们都知道现在计算机的cpu都是32位或者64位的cpu，他们一次最少读取4、8个字节，如果少于这些，反而要做一些额外的工作，会花更长的时间。 Aug 11, 2021 · 文章浏览阅读972次。本文介绍了将NV12格式的YUV数据转换为I420格式的两种方法。第一种方法是通过新建I420缓冲区并逐个复制NV12的YUV分量；第二种方法则是在原NV12数据上直接交换V和U分量。这两种方法都适用于宽度等于步长的情况。 Jun 9, 2021 · stride 和 width 是不一样的意义。一般图像数据按行储存，有时当图像的分辨率不是标准分辨率，比如55*55. V4L2_PIX_FMT_NV12_4L4 stores pixels in 4x4 tiles, and stores tiles linearly in memory. The number of luma and chroma tiles are identical, even though the tile size differ. Figure 2: Apr 27, 2018 · NV12 安卓的 MediaCodec 对于 YUV 的输入格式， COLOR_FormatYUV420SemiPlanar 支持得最好，而这种格式就是 NV12 格式。 NV12 的采样比是 4:2:0，它是 semi planar 存储方式，先存储 Y 分量，后面 Cb 和 Cr 分量一起存储，Cb 在前，Cr 在后： NV21 Oct 4, 2024 · 4. It is intended as a practical introduction for developers who need to allocate and manage memory buffers when working with QCNode processing nodes. Given the image dump originated from Intel. NV12 yuv pixel format YUV 4:2:0 image with a plane of 8 bit Y samples followed by an interleaved U/V plane containing 8 bit 2x2 subsampled colour difference samples. The following illustration shows the Y plane and the array that contains packed U and V samples. 为了内存对齐，需要将一行扩展为64. 此时每一行数据会跟随9个无意义的字节。这个矩阵的width为55，stride是64. YUV formats fall into two distinct groups, the packed formats where Y, U (Cb) and V (Cr) samples are packed together into macropixels which are stored in a single array, and the planar formats where each component is stored as a separate array, the final image being a fusing of the three separate planes. The line stride must be aligned to a multiple of 16 and the image height must be aligned to a multiple of 32. When bits < 8, the stride is expressed in bits. Mar 13, 2013 · Say we have a dump of NV12 raw video stream whose width and height are known, but not the stride value. src_ 为我们需要转换的NV12格式数据,dst_ 为转换后的i420数据那么stride代表啥??? 跨距-stride 我们都知道现在计算机的cpu都是32位或者64位的cpu，他们一次最少读取4、8个字节，如果少于这些，反而要做一些额外的工作，会花更长的时间。 NV12 is the preferred 4:2:0 pixel format for DirectX VA. V4L2_PIX_FMT_NV12_16L16 stores pixels in 16x16 tiles, and stores tiles linearly in memory. Jun 25, 2025 · The stride of a surface, sometimes called the pitch, is the width of the surface in bytes. It is yet another variant where colour information is stored at a lower resolution than the intensity data. 假设为标准分辨率或不需要内存对齐，stride和width一致即可。. Given a surface origin at the top left corner, the stride is always positive. Examples: for 24-bit RGB, the pixel stride would be 3 bytes, while it would be 4 bytes for RGBx or ARGB, and 8 bytes for ARGB64 or AYUV64. Jan 14, 2021 · On a device where there is no gap between the Y and UV planes, the uv_offset would be height times stride bytes. Feb 24, 2026 · Buffer Management Fundamentals Relevant source files Purpose and Scope This page introduces the foundational concepts of buffer management in QCNode, covering buffer descriptors, the BufferManager API, and basic memory allocation patterns. The line stride and image height must be aligned to a multiple of 4. For Oct 4, 2024 · 在准备输入时，就需要按照上面的 stride 和 validshape 准备数据了。但此时，无法解释为什么 nv12 输入时，这里的 stride 为什么必须是 -1，毕竟可以通过公式计算得到啊，为什么工具不计算好直接提供出来呢？ NV12 yuv pixel format Written by Paul Bourke August 2016 The NV12 image format is commonly found as the native format from various machine vision, and other, video cameras. The layouts of the luma and chroma planes are identical. This equivalence is not guaranteed across all devices, so it is important to observe the uv_offset value rather than attempting to compute the offset. In the NV12 case the intensity (Y) data is stored as 8 bit samples, and the colour (Cr, Cb) information as 2x2 subsampled image, this is otherwise known as 4:2:0. tkh rhf fyy wvp tft lsb nhd jnx wkt ojd voz eab clf ebl swk