How to convert from AV_PIX_FMT_VAAPI to AV_PIX_FMT_YUV420 using FFMPEG sws_scaler api?

Question

I am using below code to convert from VAAPI to YUV420 format.

     AVFrame* src, * dst;
     SwsContext* conversion_context_ = sws_getContext(videoDecoder_->width(),     videoDecoder_->height(), AV_PIX_FMT_VAAPI,scaler_->getWidth(), scaler_->getHeight(), AV_PIX_FMT_YUV420P,(int)SWS_BICUBIC,
 nullptr, nullptr, nullptr); <------------- This function is returning NULL value.
     sws_scale(conversion_context_,
                (uint8_t const * const *)src->data, src->linesize, 0, (int)height,
                dst->data, dst->linesize);

Can some one tell me why I am getting NULL value of SwsContext's pointer?

Answer 1

Fixed this issue by using below code,

SwsContext* conversion_context_ = sws_getContext(videoDecoder_->width(),     videoDecoder_->height(), AV_PIX_FMT_NV12 ,scaler_->getWidth(), scaler_->getHeight(), AV_PIX_FMT_YUV420P,(int)SWS_BICUBIC,
 nullptr, nullptr, nullptr);

So instead of AV_PIX_FMT_VAAPI option, I used AV_PIX_FMT_NV12.