hi_venc_attr

Description

Defines the VENC attributes.

Prototype

typedef struct {
    hi_payload_type type;
    hi_u32 max_pic_width;
    hi_u32 max_pic_height;
    hi_u32 buf_size;
    hi_u32 profile;
    hi_bool is_by_frame;
    hi_u32 pic_width;
    hi_u32 pic_height;
    union {
        hi_venc_h264_attr h264_attr; 
        hi_venc_h265_attr h265_attr; 
        hi_venc_jpeg_attr jpeg_attr; 
        hi_venc_prores_attr prores_attr; 
    };
}hi_venc_attr;

Members

Member	Description
type	Encode protocol.
max_pic_width	Maximum width of the source image. Must be an integral multiple of 2. This is a static attribute. Value range: [MIN_WIDTH, MAX_WIDTH], in pixels. MIN_WIDTH and MAX_WIDTH indicate the minimum width and maximum width supported by an encoding channel, respectively. For details, see Table 1.
max_pic_height	Maximum height of the source image. Must be an integral multiple of 2. This is a static attribute and does not apply to JPEG encoding. Value range: [MIN_HEIGHT, MAX_HEIGHT], in pixels. MIN_HEIGHT and MAX_HEIGHT indicate the minimum height and maximum height supported by an encoding channel, respectively. For details, see Table 1.
buf_size	Size of the stream buffer, in bytes. This is a static attribute. When hi_mpi_venc_send_jpege_frame is called to send source images for encoding, buf_size must be set to 0 during channel creation. When hi_mpi_venc_send_frame is called to send source images for video or image encoding, buf_size must be set to an integral multiple of 64 within the range [Min, Max] during channel creation. The unit is byte. (1) In video encoding scenarios, Min indicates 32 x 1024, and Max indicates 1 x 1024 x 1024 x 1024. When creating a channel, set buf_size properly to reduce the buffer overhead. You are advised to set buf_size to: source width x source height x 3/2, rounded up to the nearest multiple of 64 (64-aligned). Ensure that buf_size is within the range of [Min, Max]. In video encoding scenarios, if buf_size is set improperly, the following exceptions may occur: - Repeated re-encoding: prolongs the encoding delay, degrades the performance, and deteriorates the image quality. - Encoding failure: fails to obtain the encoding result. (2) In image encoding scenarios: Min (YUV420) = Source width 16-aligned x Source height 16-aligned x 3/2; Min (YUV422 Packed) = Source width 16-aligned x Source height 16-aligned x 2. Max = 1 x 1024 x 1024 x 1024 When creating a channel, set buf_size properly based on the largest image resolution in an actual service scenario to reduce the buffer overhead. You are advised to set buf_size to : source width x source height x multiple (5 is recommended). For example, if the resolutions of user images are 720p (1280 x 720), 1080p (1080 x 1920), and 4K (3840 x 2160), the required buf_size is calculated as follows: 3840 x 2160 x 5. In image encoding scenarios, the minimum value of buf_size is 320 x 240 x 5. This prevents the buffer from being completely occupied, which affects the encoding functionality when low-resolution (128 x 128 or less, for example) user images are input.
profile	Encoding profile. A larger value indicates better encoding quality. This is a static attribute. H.264: 0: baseline. When this value is used, B-frame encoding is not supported. 1: main profile. 2: high profile. H.265: 0: main profile. 1 (reserved): main 10 profile. Value range for JPEG: 0: baseline.
is_by_frame	Stream fetching mode select. This is a static attribute. HI_TRUE: frame mode. HI_FALSE: packet mode.
pic_width	Encoding channel width, which must be an integral multiple of MIN_ALIGN. After a channel is created, the channel width can be changed for VENC. However, the channel width cannot be changed for JPEGE. Value range: [MIN_WIDTH, max_pic_width], in pixels. MIN_WIDTH, max_pic_width, and MIN_ALIGN indicate the minimum width of an encoding channel, and the maximum width and minimum alignment (in pixels) of the image to be encoded, receptively. For details, see Table 1. For JPEG encoding, the channel width and height must meet the following condition: pic_width x pic_height ≤ max_pic_width x max_pic_height.
pic_height	Encoding channel height, which must be an integral multiple of MIN_ALIGN. Not applicable to JPEG encoding. After a channel is created, the channel height can be changed for VENC. However, the channel height cannot be changed for JPEGE. Value range: [MIN_HEIGHT, max_pic_height], in pixels. MIN_HEIGHT, max_pic_height, and MIN_ALIGN indicate the minimum height of an encoding channel, and the maximum height and minimum alignment (in pixels) of the image to be encoded, receptively. For details, see Table 1. For JPEG encoding, the channel width and height must meet the following condition: pic_width x pic_height ≤ max_pic_width x max_pic_height.
h264_attr	Attributes of the encode protocol.
h265_attr	Attributes of the encode protocol.
jpeg_attr	Attributes of the encode protocol. Reserved.
prores_attr	Attributes of the encode protocol. Reserved.

References

MIN_WIDTH, MAX_WIDTH, MIN_HEIGHT, MAX_HEIGHT, and MIN_ALIGN indicate the minimum width, maximum width, minimum height, maximum height, and minimum alignment (in pixels) of an encoding channel, receptively.

**Table 1** Encoding channel width and height
W/H (pixel)	H.264	H.265	JPEG
MIN_WIDTH	128	128	32
MAX_WIDTH	4096	4096	8192
MIN_HEIGHT	128	128	32
MAX_HEIGHT	4096	4096	8192
MIN_ALIGN	2	2	2

Parent topic: VENC/JPEGE