[FFmpeg-devel] [PATCH] avcodec/v4l2: set sizeimage param for non-raw buffers [fixes #6716]

[wm4]

On Wed,  4 Oct 2017 11:17:24 +0200
Jorge Ramirez-Ortiz <jorge.ramirez-ortiz at linaro.org> wrote:

> Some V4L2 drivers fail to allocate buffers when sizeimage is not set
> to a max value. This is indeed the case for sp5-mfc [1]
> 
> Most drivers should be able to calculate this value from the frame
> dimensions and format - or at least have their own default.
> 
> However since this work around should not impact those drivers doing
> the "right thing" this commit just provides such a default.
> 
> [1] linux.git/drivers/media/platform/s5p-mfc
> ---
>  libavcodec/v4l2_context.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c
> index 297792f..2707ef5 100644
> --- a/libavcodec/v4l2_context.c
> +++ b/libavcodec/v4l2_context.c
> @@ -92,6 +92,8 @@ static inline int v4l2_type_supported(V4L2Context *ctx)
>  
>  static inline void v4l2_save_to_context(V4L2Context* ctx, struct v4l2_format_update *fmt)
>  {
> +    const int MAX_SIZEIMAGE = 2 * 1024 * 1024;
> +
>      ctx->format.type = ctx->type;
>  
>      if (fmt->update_avfmt)
> @@ -101,13 +103,21 @@ static inline void v4l2_save_to_context(V4L2Context* ctx, struct v4l2_format_upd
>          /* update the sizes to handle the reconfiguration of the capture stream at runtime */
>          ctx->format.fmt.pix_mp.height = ctx->height;
>          ctx->format.fmt.pix_mp.width = ctx->width;
> -        if (fmt->update_v4l2)
> +        if (fmt->update_v4l2) {
>              ctx->format.fmt.pix_mp.pixelformat = fmt->v4l2_fmt;
> +
> +            /* s5p-mfc requires the user to specify MAX buffer size */
> +            ctx->format.fmt.pix_mp.plane_fmt[0].sizeimage = MAX_SIZEIMAGE;
> +        }
>      } else {
>          ctx->format.fmt.pix.height = ctx->height;
>          ctx->format.fmt.pix.width = ctx->width;
> -        if (fmt->update_v4l2)
> +        if (fmt->update_v4l2) {
>              ctx->format.fmt.pix.pixelformat = fmt->v4l2_fmt;
> +
> +            /* s5p-mfc requires the user to specify MAX buffer size */
> +            ctx->format.fmt.pix.sizeimage = MAX_SIZEIMAGE;
> +        }
>      }
>  }
>  

Isn't this something that should be fixed in the driver?

Why 2MB?