[FFmpeg-devel] [PATCH] avcodec: v4l2_m2m: reduce the minimum amount of buffers

[Jorge Ramirez-Ortiz]

On 04/05/2018 06:42 PM, Maxime Jourdan wrote:
> Reduce the minimum amount of CAPTURE and OUTPUT buffers to 1.

makes sense to me if that is indeed the case.
could you provide a real life use case?

>
> There are drivers that may work with such drastic settings,
> and FFmpeg doesn't complain.
> ---
>  libavcodec/v4l2_m2m.h     | 2 +-
>  libavcodec/v4l2_m2m_dec.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/v4l2_m2m.h b/libavcodec/v4l2_m2m.h
> index 452bf0d9bc..68e4e5d6c6 100644
> --- a/libavcodec/v4l2_m2m.h
> +++ b/libavcodec/v4l2_m2m.h
> @@ -38,7 +38,7 @@
>  #define V4L_M2M_DEFAULT_OPTS \
>      { "num_output_buffers", "Number of buffers in the output context",\
> -        OFFSET(num_output_buffers), AV_OPT_TYPE_INT, { .i64 = 16 }, 
> 6, INT_MAX, FLAGS }
> +        OFFSET(num_output_buffers), AV_OPT_TYPE_INT, { .i64 = 16 }, 
> 1, INT_MAX, FLAGS }
>  typedef struct V4L2m2mContext {
>      char devname[PATH_MAX];
> diff --git a/libavcodec/v4l2_m2m_dec.c b/libavcodec/v4l2_m2m_dec.c
> index bca45be148..5196680bbb 100644
> --- a/libavcodec/v4l2_m2m_dec.c
> +++ b/libavcodec/v4l2_m2m_dec.c
> @@ -198,7 +198,7 @@ static av_cold int v4l2_decode_init(AVCodecContext 
> *avctx)
>  static const AVOption options[] = {
>      V4L_M2M_DEFAULT_OPTS,
>      { "num_capture_buffers", "Number of buffers in the capture context",
> -        OFFSET(num_capture_buffers), AV_OPT_TYPE_INT, {.i64 = 20}, 
> 20, INT_MAX, FLAGS },
> +        OFFSET(num_capture_buffers), AV_OPT_TYPE_INT, {.i64 = 20}, 1, 
> INT_MAX, FLAGS },
>      { NULL},
>  };
> -- 
> 2.16.2