<div class="gmail_quote">On Fri, Oct 15, 2010 at 9:33 PM, Gwenole Beauchesne <<a href="mailto:gbeauchesne@splitted-desktop.com">gbeauchesne@splitted-desktop.com</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> Hi,<div class="im"> On Thu, 14 Oct 2010, Varun Dua wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> I am decoding a H.264 video using Nvidia's Graphics Card and Vaapi Library on Ubuntu 10.04. I am able to decode an entire video and display it using vaPutSurface, no problems at all. Now I need the data in RGBA format so I get the data in BRGA format which is supported in my implementation (I can convert it into RGBA). </blockquote> </div> Note that retrieving the decoded pixels can be a slow operation. Also note that only the vdpau-video driver supports BGRA read-back. In particular, only the NVIDIA implementation. i.e. I would not rely on that.<div class="im"> <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> VAImage vaimage; unsigned char *imagedata = NULL; FILE *fp1; char file[100]; printf("%x\n",myimgfmt.fourcc); vastatus = pfn_vaCreateImage(vaapi->display,&myimgfmt,avcc->width,avcc->height,&vaimage); checkVaStatus(); pfn_vaGetImage (vaapi->display,va_surface_ids[current_surface],0,0,avcc->width,avcc->height,vaimage.image_id); checkVaStatus(); imagedata = (char *)malloc(vaimage.data_size*sizeof(char)); pfn_vaMapBuffer(vaapi->display,vaimage.buf,(void *)&imagedata); </blockquote> </div> vaMapBuffer() returns the mapped region in imagedata. i.e. you must not allocate, neither free that pointer;<div class="im"> <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> sprintf(file,"brga/frame%d.raw",framenumber++); fp1 = fopen(file,"wb"); fwrite(imagedata,vaimage.data_size*sizeof(unsigned char),1,fp1); fclose(fp1); free(imagedata); imagedata = NULL; vastatus = pfn_vaUnmapBuffer(vaapi->display,vaimage.buf); checkVaStatus(); vastatus = vaDestroyImage(vaapi->display,vaimage.image_id); Everthing is working fine except that I am getting Segmentaion fault at vaDestroyImage. I am unable to correct this error. Can anybody help me with that ? </blockquote> </div> Drop the imagedata = ...; and free(imagedata); lines. Regards, Gwenole. </blockquote></div> Thanks a lot. Varun Dua