Function: vdec_send_skipped_frame

Applicability

Product	Supported (√/x)
Atlas A3 training products/Atlas A3 inference products	√
Atlas A2 training products/Atlas A2 inference products	√
Atlas training products	√
Atlas inference products	√
Atlas 200I/500 A2 inference products	√

Function Usage

Feeds a stream (the input buffer) to the decoder for decoding. The callback function outputs 0 for dvpp_pic_desc when the decoding is complete, instead of the decode result. This API is asynchronous.

Prototype

C Prototype

aclError aclvdecSendSkippedFrame(aclvdecChannelDesc *channelDesc, acldvppStreamDesc *input, aclvdecFrameConfig *config, void *userData)

Python Function

ret = acl.media.vdec_send_skipped_frame(vdec_channel_desc, dvpp_stream_desc, vdec_frame_config, user_data)

Parameter Description

Parameter	Description
vdec_channel_desc	Int, pointer address of the channel description. It must be the same as dvpp_channel_desc passed to the acl.media.dvpp_create_channel call. Call the acl.media.vdec_set_channel_desc APIs to set attributes of the channel description, including the decoding channel ID, thread, callback function, and video coding protocol. NOTE: For the Atlas training products, due to software restrictions, it is not allowed to set the channel description attributes by calling acl.media.vdec_set_channel_desc_ref_frame_num. If the API is called, an error is returned.
dvpp_stream_desc	Int, pointer address of the input stream description. You need to allocate the input buffer in advance. Call acl.media.dvpp_create_stream_desc to create an image description. Call the acl.media.dvpp_set_stream_desc APIs to set the attributes (such as the stream format) of video streams. The input stream format is subject to the format set in the channel description. The acl.media.dvpp_set_stream_desc_format call to set the input stream format is invalid. For details about requirements on the resolution and format of the input video stream, see Functions and Restrictions.
vdec_frame_config	Int, pointer address of the decoding configuration. This parameter is reserved and can be set to 0 currently.
user_data	Python object, pointer address of the user-defined data. If you want to obtain the sequence number of the decoded frame, define the user_data parameter. Then, the sequence number can be passed to the VDEC callback function to determine the frame to be processed.

Return Value Description

Return Value	Description
ret	Int, error code: 0 on success; else, failure.

Restrictions

This API is asynchronous. The API call delivers a task rather than executes a task. After this API is called, call the synchronization API (for example, acl.rt.synchronize_stream) to ensure that the task is complete.

The channel passed to this call must have been created. Otherwise, an error code is returned.
A stream must be fed in frame mode, which means that a complete frame must be fed in every call to this API.
It is not supported to feed empty packets with eos set to 0 (the stream length is 0 or the stream address is empty).
It is not allowed to feed frames with eos set to 1.
Due to stream exception or decoding timeout, the acl.media.vdec_send_frame API may fail to send frames or the EOS frame. You are advised to obtain the return code of this API when writing code. If this API fails to be called, handle the exception.
acl.rt.launch_callback is encapsulated in acl.media.vdec_send_skipped_frame to add a callback function to be executed on the host to the stream task queue. To implement the VDEC function, acl.rt.launch_callback does not need to be called separately.

Parent topic: VDEC