Video decoder on Cuda ffmpeg

Question

I starting to implement custum video decoder that utilize cuda HW decoder to generate YUV frame for next to encode it.

How can I fill "CUVIDPICPARAMS" struc ??? Is it possible?

My algorithm are:

For get video stream packet I'm use ffmpeg-dev libs avcodec, avformat...

My steps:

1) Open input file:

avformat_open_input(&ff_formatContext,in_filename,nullptr,nullptr);

2) Get video stream property's:

avformat_find_stream_info(ff_formatContext,nullptr);

3) Get video stream:

ff_video_stream=ff_formatContext->streams[i];

4) Get CUDA device and init it:

cuDeviceGet(&cu_device,0);
CUcontext cu_vid_ctx;

5) Init video CUDA decoder and set create params:

CUVIDDECODECREATEINFO *cu_decoder_info=new CUVIDDECODECREATEINFO;
memset(cu_decoder_info,0,sizeof(CUVIDDECODECREATEINFO));
...
cuvidCreateDecoder(cu_video_decoder,cu_decoder_info);

6)Read frame data to AVpacket

av_read_frame(ff_formatContext,ff_packet);

AND NOW I NEED decode frame packet on CUDA video decoder, in theoretical are:

cuvidDecodePicture(pDecoder,&picParams);

BUT before I need fill CUVIDPICPARAMS

CUVIDPICPARAMS picParams;//=new CUVIDPICPARAMS; memset(&picParams, 0, sizeof(CUVIDPICPARAMS));

HOW CAN I FILL "CUVIDPICPARAMS" struc ???

typedef struct _CUVIDPICPARAMS
{
    int PicWidthInMbs;      // Coded Frame Size
    int FrameHeightInMbs;   // Coded Frame Height
    int CurrPicIdx;         // Output index of the current picture
    int field_pic_flag;     // 0=frame picture, 1=field picture
    int bottom_field_flag;  // 0=top field, 1=bottom field (ignored if field_pic_flag=0)
    int second_field;       // Second field of a complementary field pair
    // Bitstream data
    unsigned int nBitstreamDataLen;        // Number of bytes in bitstream data buffer
    const unsigned char *pBitstreamData;   // Ptr to bitstream data for this picture (slice-layer)
    unsigned int nNumSlices;               // Number of slices in this picture
    const unsigned int *pSliceDataOffsets; // nNumSlices entries, contains offset of each slice within the bitstream data buffer
    int ref_pic_flag;       // This picture is a reference picture
    int intra_pic_flag;     // This picture is entirely intra coded
    unsigned int Reserved[30];             // Reserved for future use
    // Codec-specific data
    union {
        CUVIDMPEG2PICPARAMS mpeg2;          // Also used for MPEG-1
        CUVIDH264PICPARAMS h264;
        CUVIDVC1PICPARAMS vc1;
        CUVIDMPEG4PICPARAMS mpeg4;
        CUVIDJPEGPICPARAMS jpeg;
        unsigned int CodecReserved[1024];
    } CodecSpecific;
} CUVIDPICPARAMS;

typedef struct _CUVIDH264PICPARAMS
{
    // SPS
    int log2_max_frame_num_minus4;
    int pic_order_cnt_type;
    int log2_max_pic_order_cnt_lsb_minus4;
    int delta_pic_order_always_zero_flag;
    int frame_mbs_only_flag;
    int direct_8x8_inference_flag;
    int num_ref_frames;             // NOTE: shall meet level 4.1 restrictions
    unsigned char residual_colour_transform_flag;
    unsigned char bit_depth_luma_minus8;    // Must be 0 (only 8-bit supported)
    unsigned char bit_depth_chroma_minus8;  // Must be 0 (only 8-bit supported)
    unsigned char qpprime_y_zero_transform_bypass_flag;
    // PPS
    int entropy_coding_mode_flag;
    int pic_order_present_flag;
    int num_ref_idx_l0_active_minus1;
    int num_ref_idx_l1_active_minus1;
    int weighted_pred_flag;
    int weighted_bipred_idc;
    int pic_init_qp_minus26;
    int deblocking_filter_control_present_flag;
    int redundant_pic_cnt_present_flag;
    int transform_8x8_mode_flag;
    int MbaffFrameFlag;
    int constrained_intra_pred_flag;
    int chroma_qp_index_offset;
    int second_chroma_qp_index_offset;
    int ref_pic_flag;
    int frame_num;
    int CurrFieldOrderCnt[2];
    // DPB
    CUVIDH264DPBENTRY dpb[16];          // List of reference frames within the DPB
    // Quantization Matrices (raster-order)
    unsigned char WeightScale4x4[6][16];
    unsigned char WeightScale8x8[2][64];
    // FMO/ASO
    unsigned char fmo_aso_enable;
    unsigned char num_slice_groups_minus1;
    unsigned char slice_group_map_type;
    signed char pic_init_qs_minus26;
    unsigned int slice_group_change_rate_minus1;
    union
    {
        unsigned long long slice_group_map_addr;
        const unsigned char *pMb2SliceGroupMap;
    } fmo;
    unsigned int  Reserved[12];
    // SVC/MVC
    union
    {
        CUVIDH264MVCEXT mvcext;
        CUVIDH264SVCEXT svcext;
    };
} CUVIDH264PICPARAMS;

Answer 1

This is the purpose of the CUvideoparser object. You feed it the data stream frame by frame through cuvidParseVideoData, and it calls you back with CUVIDPICPARAMS ready to pass to the decoder when it detects it has a complete frame ready.

All this and more is very well illustrated in the D3D9 decode sample, available here. I suggest studying it in detail because there's not much documentation for this API outside of it.