RocVideoDecoder API reference

RocVideoDecoder API reference#

2026-09-23

4 min read time

Applies to Linux

The RocVideoDecoder utility class is exposed in utils/rocvideodecode/roc_video_dec.h.

class RocVideoDecoder#
#include <roc_video_dec.h>

High-level video decoder utility class that wraps the rocDecode core APIs to create, control, and destroy the hardware decoder, and to decode and retrieve frames on the GPU.

Public Functions

RocVideoDecoder(int device_id, OutputSurfaceMemoryType out_mem_type, rocDecVideoCodec codec, bool force_zero_latency = false, const Rect *p_crop_rect = nullptr, bool extract_user_SEI_Message = false, uint32_t disp_delay = 0, int max_width = 0, int max_height = 0, uint32_t clk_rate = 1000, bool skip_init = false)#

Construct a new Roc Video Decoder object.

Parameters:

  • device_id – : device_id to initialize HIP and VCN

  • out_mem_type – : out_mem_type for the decoded surface

  • codec – : codec type

  • force_zero_latency – : to force zero latency (output in decoding orde)

  • p_crop_rect – : to crop output

  • extract_user_SEI_Message – : enable to extract SEI

  • disp_delay – : output delayed by #disp_delay surfaces

  • max_width – : Max. width for the output surface

  • max_height – : Max. height for the output surface

  • clk_rate – : FPS clock-rate

inline uint32_t GetWidth()#

Get the output frame width.

inline int GetDecodeWidth()#

This function is used to get the actual decode width.

inline uint32_t GetHeight()#

Get the output frame height.

inline int GetChromaHeight()#

This function is used to get the current chroma height.

inline int GetNumChromaPlanes()#

This function is used to get the number of chroma planes.

inline virtual int GetFrameSize()#

This function is used to get the current frame size based on pixel format.

inline uint32_t GetBitDepth()#

Get the Bit Depth and BytesPerPixel associated with the pixel format.

Returns:

uint32_t

inline size_t GetSurfaceSize()#

Functions to get the output surface attributes.

const char *GetCodecFmtName(rocDecVideoCodec codec_id)#

Get the name of the output format.

Parameters:

codec_id –

Returns:

std::string

const char *GetSurfaceFmtName(rocDecVideoSurfaceFormat surface_format_id)#

function to return the name from surface_format_id

Parameters:

surface_format_id – - enum for surface format

Returns:

const char*

virtual bool GetOutputSurfaceInfo(OutputSurfaceInfo **surface_info)#

Get the pointer to the Output Image Info.

Parameters:

surface_info – ptr to output surface info

Returns:

true

Returns:

false

bool SetReconfigParams(ReconfigParams *p_reconfig_params, bool b_force_reconfig_flush = false)#

Function to set the Reconfig Params object.

Parameters:

p_reconfig_params – pointer to reconfig params struct

Returns:

true : success

Returns:

false : fail

int FlushAndReconfigure()#

Function to force Reconfigure Flush: needed for random seeking to key frames.

Returns:

int 1: Success 0: Fail

virtual int DecodeFrame(const uint8_t *data, size_t size, int pkt_flags, int64_t pts = 0, int *num_decoded_pics = nullptr)#

this function decodes a frame and returns the number of frames available for display

Parameters:

  • data – - pointer to the data buffer that is to be decoded

  • size – - size of the data buffer in bytes

  • pts – - presentation timestamp

  • flags – - video packet flags

  • num_decoded_pics – - number of pictures decoded in this call

Returns:

int - num of frames to display

virtual uint8_t *GetFrame(int64_t *pts)#

This function returns a decoded frame and timestamp. This should be called in a loop fetching all the available frames.

virtual bool ReleaseFrame(int64_t pTimestamp, bool b_flushing = false)#

function to release frame after use by the application: Only used with “OUT_SURFACE_MEM_DEV_INTERNAL”

Parameters:

  • pTimestamp – - timestamp of the frame to be released (unmapped)

  • b_flushing – - true when flushing

Returns:

true - success

Returns:

false - failed

void GetDeviceinfo(std::string &device_name, std::string &gcn_arch_name, int &pci_bus_id, int &pci_domain_id, int &pci_device_id)#

utility function to save image to a file

Get the Device info for the current device

Parameters:

  • output_file_name – - file to write

  • dev_mem – - dev_memory pointer of the frame

  • image_info – - output image info

  • is_output_RGB – - to write in RGB

  • device_name –

  • gcn_arch_name –

  • pci_bus_id –

  • pci_domain_id –

  • pci_device_id –

virtual void SaveFrameToFile(std::string output_file_name, void *surf_mem, OutputSurfaceInfo *surf_info, size_t rgb_image_size = 0)#

Helper function to dump decoded output surface to file.

Parameters:

  • output_file_name – - Output file name

  • dev_mem – - pointer to surface memory

  • surf_info – - surface info

  • rgb_image_size – - image size for rgb (optional). A non_zero value indicates the surf_mem holds an rgb interleaved image and the entire size will be dumped to file

virtual void ResetSaveFrameToFile()#

Helper function to close an existing file and dump to new file in case of multiple files using same decoder.

inline int32_t GetNumOfFlushedFrames()#

Get the Num Of Flushed Frames from video decoder object.

Returns:

int32_t

void WaitForDecodeCompletion()#

Function to wait for the decode completion of the last submitted picture.

bool CodecSupported(int device_id, rocDecVideoCodec codec_id, uint32_t bit_depth)#

Check if the given Video Codec is supported on the given GPU.

Returns:

rocDecStatus

virtual int ReconfigureDecoder(RocdecVideoFormat *p_video_format)#

This function reconfigure decoder if there is a change in sequence params.

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