Functions and Restrictions
The
The
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Function Description
VENC encodes YUV420SP NV12/NV21 8-bit images into H.264/H.265 video streams.
Resolution Restrictions
- Input resolution range:
Model
Resolution Range
Atlas inference products The width and height range from 128 to 4096. For H.264 streams, the maximum resolution must not exceed 4096 × 2304.
Atlas 200I/500 A2 inference products 114 × 114 to 8192 × 8192
- Output stream resolution:
VENC only encodes images and does not change the image resolution. Therefore, the resolution of the output image is the same as that of the input image.
Restrictions on Stream/Image Formats, Width and Height Alignment, and Buffers
To implement the VENC function:
- Input buffer
Call acldvppMalloc or acldvppFree to allocate or free the input buffer on the device. The buffer lifetime is managed by the user. For details about the buffer size, see the formula in the following table.
For the
Atlas inference products , aclrtMalloc and aclrtFree can be called to allocate and free input buffer, respectively. During buffer allocation, you are advised to allocate buffer of the ACL_MEM_MALLOC_HUGE_FIRST type. Huge page buffer has better performance and therefore is preferred. The lifetime of the buffer is also managed by the user. For details about the buffer size, see the calculation formula in the following table. - Output buffer
Input Format |
Input Width and Height |
Input Width Stride, Height Stride, and Buffer Size |
Output Format |
|---|---|---|---|
YUV420SP NV12 8-bit |
Width: Must be a multiple of 2. Height: Must be a multiple of 2. |
Width stride: Round up the width to the nearest multiple of 16. The height stride does not need to be configured. Buffer size (in bytes) = Width stride × Height × 3/2 |
|
YUV420SP NV21 8-bit |
For details about the definition of the input image format, see acldvppPixelFormat. For details about the concepts such as width stride and height stride, see Terminology.