[FFmpeg-devel] Hardware CSC conversion segfault

[Michael Niedermayer]

On Fri, Jul 12, 2013 at 10:09:55PM +0000, Umar Qureshey wrote:
> Hi,
> I am a newbie in the ffmpeg world.  
> I am attempting to offload the colorspace conversion to hardware in the i.MX6 SoC.  So far I have the following:
> 
> static int imx6_yuv420_to_rgb565le(SwsContext *c, uint8_t *src[], int srcStride[],
>                            int srcSliceY, int srcSliceH,
>                            uint8_t *dst[], int dstStride[])
> {
>     int isize, osize, ret = 0, i;
>     void *inbuf=NULL, *outbuf=NULL;
> 
>     //Clear task struct.
>     memset(&c->task, 0, sizeof(c->task));
>     //Open the Image Processing Unit.
>     c->fd_ipu = open("/dev/mxc_ipu", O_RDWR, 0);
>     if (c->fd_ipu < 0)
>     {
>         av_log(c, AV_LOG_ERROR, "open ipu dev fail\n");
>         return 0;
>     }
>     //1)  Allocate physical memory to for image processing unit.
>     //1a) Calculate size of input/output buffers.
>     INPUT_WIDTH(c) = c->srcW;
>     OUTPUT_WIDTH(c) = c->dstW;
>     INPUT_HEIGHT(c) = c->srcH;
>     OUTPUT_HEIGHT(c) = c->dstH;
>     INPUT_FORMAT(c) = IPU_PIX_FMT_YUV420P;
>     OUTPUT_FORMAT(c) = IPU_PIX_FMT_RGB565;
>     OUTPUT_ROTATION(c) = 0;
>     isize = INPUT_PADDR(c) = (INPUT_WIDTH(c) * INPUT_HEIGHT(c) * fmt_to_bpp(INPUT_FORMAT(c))/8);
>     osize = OUTPUT_PADDR(c) = (OUTPUT_WIDTH(c) * OUTPUT_HEIGHT(c) * fmt_to_bpp(OUTPUT_FORMAT(c))/8);
>     //1b) Allocate contiguous physical memory for input/output image.
>     //    input.paddr and output.paddr contains the amount needed.
>     //    These values will be replaced with physical address on success.
>     ret = ioctl(c->fd_ipu, IPU_ALLOC, &INPUT_PADDR(c));
>     if (ret < 0)
>     {
>         av_log(c, AV_LOG_ERROR, "physical memory allocation of input buffer failed: (errno = %d)\n", errno);
>         goto done;
>     }
>     ret = ioctl(c->fd_ipu, IPU_ALLOC, &OUTPUT_PADDR(c));
>     if (ret < 0)
>     {
>         av_log(c, AV_LOG_ERROR, "physical memory allocation of output buffer failed: (errno = %d)\n", errno);
>         goto done;
>     }
>     //2) Get the virtual addresses for the physical input/output buffers so we can access them from userland here.
>     inbuf = mmap(0, isize, PROT_READ | PROT_WRITE, MAP_SHARED, c->fd_ipu, INPUT_PADDR(c));
>     if (!inbuf)
>     {
>         av_log(c, AV_LOG_ERROR, "inbuf mmap failed\n");
>         goto done;
>     }
>     outbuf = mmap(0, osize, PROT_READ | PROT_WRITE, MAP_SHARED, c->fd_ipu, OUTPUT_PADDR(c));
>     if (!outbuf)
>     {
>         av_log(c, AV_LOG_ERROR, "outbuf mmap failed\n");
>         goto done;
>     }
>     //3) Copy the raw image to the input IPU buffer.
>     memcpy(inbuf, src[0], isize);               //<-- SEG FAULT at memcpy on the second invocation of this function.
>     //4) Perform the colorspace conversion.
>     ret = ioctl(c->fd_ipu, IPU_QUEUE_TASK, &c->task);
>     if (ret < 0)
>     {
>         av_log(c, AV_LOG_ERROR, "ioct IPU_QUEUE_TASK fail %x\n", ret);
>         goto done;
>     }
>     //5) Copy converted buffer.
>     memcpy(dst[0], outbuf, osize);
> done:
>     if (outbuf)
>         munmap(outbuf, osize);
>     if (OUTPUT_PADDR(c))
>         ioctl(c->fd_ipu, IPU_FREE, &OUTPUT_PADDR(c));
>     if (inbuf)
>         munmap(inbuf, isize);
>     if (INPUT_PADDR(c))
>         ioctl(c->fd_ipu, IPU_FREE, &INPUT_PADDR(c));
>     if (c->fd_ipu)
>         close(c->fd_ipu);
>     return srcSliceH;
> }
> 
> I am getting a seg fault as indicated above when copying from the src[0] to inbuf.
> My question is does src hold pointer to one contiguous memory buffer holding the different planes of YUV data or can they discontinuous?

discontinuous


> The hardware simply takes a contiguous memory buffer of a specified data format (YUV420P in this case) and outputs a buffer of a specified data format (RGB565LE in this case).
> Any tips appreciated.
> Thx
> _______________________________________________
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> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Republics decline into democracies and democracies degenerate into
despotisms. -- Aristotle
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