VENC Functions and Restrictions

The Atlas training product does not support the VENC function described in this section.

For the Atlas A2 training product / Atlas A2 inference product , this function is not supported.

For the Atlas A3 training product / Atlas A3 inference product , this function is not supported.

Description

Video Encoder (VENC) encodes YUV420SP NV12/NV21 8-bit images into H.264/H.265 video streams.

Resolution Restrictions

Input image resolution range

Version	Resolution Range
Atlas inference product	The width and height range from 128 to 4096. For H.264 streams, the maximum resolution must not exceed 4096 x 2304.
Atlas 200I/500 A2 inference product	114 x 114 to 8192 x 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 Buffer Allocation and Freeing APIs

For details about the input memory size, see the calculation formula in Table 1. The output memory does not need to be managed by users but is managed by the system.

Version	Buffer Allocation/Freeing API
Atlas inference product	During VENC video encoding, allocate or free the input buffer on the device by calling acl.himpi.dvpp_malloc/acl.himpi.dvpp_free. The buffer lifetime is managed by the user.
Atlas 200I/500 A2 inference product	During VENC video encoding, the following two types of buffer allocation/freeing APIs are supported: Allocate or free the input buffer on the device by calling acl.rt.malloc/acl.rt.free. The buffer lifetime is managed by the user. Allocate or free the input buffer on the device by calling acl.himpi.dvpp_malloc/acl.himpi.dvpp_free. The buffer lifetime is managed by the user. The memory allocated by calling the acl.himpi.dvpp_malloc API is the dedicated memory for media data processing. However, the address space of the dedicated memory is limited. If memory planning is concerned or memory resources are limited, you are advised to call the acl.rt.malloc API to allocate memory.
Atlas inference product	In the VENC scenario, the following two types of buffer allocation/freeing APIs are supported for storing input image data: Allocate or free the input buffer on the device by calling acl.rt.malloc/acl.rt.free. The buffer lifetime is managed by the user. 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. Allocate or free the input buffer on the device by calling acl.himpi.dvpp_malloc/acl.himpi.dvpp_free. The buffer lifetime is managed by the user. When using VENC, if non-input image data (such as the QpMap table information) is stored, only acl.himpi.dvpp_malloc/acl.himpi.dvpp_free can be called to allocate and free the input buffer on the device. The buffer lifetime is managed by the user. Note: The memory allocated by calling the acl.himpi.dvpp_malloc API is dedicated for media data processing. However, the address space of the dedicated memory is limited. If memory planning is concerned or memory resources are limited, you are advised to call the acl.rt.malloc API to allocate memory.

Version

Buffer Allocation/Freeing API

Atlas inference product

During VENC video encoding, allocate or free the input buffer on the device by calling acl.himpi.dvpp_malloc/acl.himpi.dvpp_free. The buffer lifetime is managed by the user.

Atlas 200I/500 A2 inference product

During VENC video encoding, the following two types of buffer allocation/freeing APIs are supported:

Allocate or free the input buffer on the device by calling acl.rt.malloc/acl.rt.free. The buffer lifetime is managed by the user.
Allocate or free the input buffer on the device by calling acl.himpi.dvpp_malloc/acl.himpi.dvpp_free. The buffer lifetime is managed by the user.

The memory allocated by calling the acl.himpi.dvpp_malloc API is the dedicated memory for media data processing. However, the address space of the dedicated memory is limited. If memory planning is concerned or memory resources are limited, you are advised to call the acl.rt.malloc API to allocate memory.

Atlas inference product

In the VENC scenario, the following two types of buffer allocation/freeing APIs are supported for storing input image data:

Allocate or free the input buffer on the device by calling acl.rt.malloc/acl.rt.free. The buffer lifetime is managed by the user. 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.
Allocate or free the input buffer on the device by calling acl.himpi.dvpp_malloc/acl.himpi.dvpp_free. The buffer lifetime is managed by the user.

When using VENC, if non-input image data (such as the QpMap table information) is stored, only acl.himpi.dvpp_malloc/acl.himpi.dvpp_free can be called to allocate and free the input buffer on the device. The buffer lifetime is managed by the user.

Note: The memory allocated by calling the acl.himpi.dvpp_malloc API is dedicated for media data processing. However, the address space of the dedicated memory is limited. If memory planning is concerned or memory resources are limited, you are advised to call the acl.rt.malloc API to allocate memory.

Restrictions on Stream/Image Formats, Width and Height Alignment, and Buffers

For details about the definition of the input image format, see hi_pixel_format. For details about the concepts such as width stride and height stride, see Terminology.

Parent topic: VENC/JPEGE APIs