Functions and Restrictions

Function Description

JPEG Encoder (JPEGE) encodes YUV images into JPEG image files, for example, .jpg files.

Resolution Restrictions

Input resolution range:

Model	Resolution Range
Atlas A3 training products/Atlas A3 inference products Atlas A2 training products/Atlas A2 inference products Atlas inference products Atlas training products	32 × 32 to 8192 × 8192
Atlas 200I/500 A2 inference products	32 × 32 to 16384 × 16384

Model

Resolution Range

Atlas A3 training products/Atlas A3 inference products

Atlas A2 training products/Atlas A2 inference products

Atlas inference products

Atlas training products

32 × 32 to 8192 × 8192

Atlas 200I/500 A2 inference products

32 × 32 to 16384 × 16384

Output resolution range:
JPEGE 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 Image Formats, Width and Height Alignment, and Buffers

During JPEGE image encoding, acldvppMalloc and acldvppFree are called to allocate and free the input and output buffers on the device. The buffer lifetime is managed by the user.

For details about the input buffer size, see the formula in the following table.
The output buffer size is the actual size of space occupied by the encoded image, and can be predicted by calling acldvppJpegPredictEncSize.

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.

**Table 1** Restrictions on the image format, width and height alignment, and buffer size
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 or any multiple of 16, for example, 128 (which offers better performance). The height stride supports the following configurations: Set it to the height of the input image. Alternatively, round up the input height to the nearest multiple of 16 (at least 32). For example, when the JPEGE input comes from the JPEGD output whose height is rounded up to the nearest multiple of 16. Buffer size (in bytes) = Width stride × Height stride × 3/2	JPEG, for example, .jpg. Only Huffman coding is supported. Arithmetic coding and progressive coding are not supported.
YUV420SP NV21 8-bit
YUV422 Packed YUYV 8-bit	Width: Must be a multiple of 2. Height: No alignment requirement.	Width stride: Double the width and then round up the result to the nearest multiple of 16. The height stride supports the following configurations: Set it to the height of the input image. Alternatively, round up the input height to the nearest multiple of 16 (at least 32). For example, when the JPEGE input comes from the JPEGD output whose height is rounded up to the nearest multiple of 16. Buffer size (in bytes) = Width stride × Height stride
YUV422 Packed UYVY 8-bit
YUV422 Packed YVYU 8-bit
YUV422 Packed VYUY 8-bit

Parent topic: JPEGE