[FFmpeg-devel] [PATCH] Implement avfilter_make_format_list2(enum PixelFormat pix_fmt, ...)

[Michael Niedermayer]

On Sat, Oct 17, 2009 at 01:55:39AM +0200, Stefano Sabatini wrote:
> Hi,
> 
> the interface of AVFilterFormats *avfilter_make_format_list(int len,
> ...) is quite brittle, since it requires the exact number of
> parameters to be passed, especially with long lists it is quite easy
> to get it wrong or get it de-synched for example if a new format is
> added to the list.
> 
> This new function provides a more robust / convenient interface, the
> list is terminated by PIX_FMT_NONE and so the user doesn't need to
> manually adjust the value of len.
> 
> No it doesn't look very convenient to factorize the code
> avfilter_make_format_list() with avfilter_make_format_list(), anyway
> my idea was to deprecate the old interface, or maybe simply to change
> the avfilter_make_format_list() interface as the API is declared
> non-stable yet.
> 
> Regards.
> -- 
> FFmpeg = Friendly & Friendly Monstrous Philosofic Enhancing Geisha

>  avfilter.h |    9 +++++++++
>  formats.c  |   27 +++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+)
> 31802b3c59325cbbdab58c6e275b3e083293b604  lavfi-make-format-list2.patch
> Index: ffmpeg/libavfilter/avfilter.h
> ===================================================================
> --- ffmpeg.orig/libavfilter/avfilter.h	2009-10-17 01:38:34.000000000 +0200
> +++ ffmpeg/libavfilter/avfilter.h	2009-10-17 01:39:12.000000000 +0200
> @@ -180,6 +180,15 @@
>  AVFilterFormats *avfilter_make_format_list(int len, ...);
>  
>  /**
> + * Helper function to create a list of supported formats. This is intended
> + * for use in AVFilter->query_formats().
> + * @param pix_fmt the first pixel format of the provided list
> + * @param ... a list of the supported pixel formats, terminated by PIX_FMT_NONE.
> + * @return the format list, with no existing references
> + */
> +AVFilterFormats *avfilter_make_format_list2(enum PixelFormat pix_fmt, ...);
> +
> +/**
>   * Returns a list of all colorspaces supported by FFmpeg.
>   */
>  AVFilterFormats *avfilter_all_colorspaces(void);
> Index: ffmpeg/libavfilter/formats.c
> ===================================================================
> --- ffmpeg.orig/libavfilter/formats.c	2009-10-17 01:39:45.000000000 +0200
> +++ ffmpeg/libavfilter/formats.c	2009-10-17 01:51:21.000000000 +0200
> @@ -87,6 +87,33 @@
>      return ret;
>  }
>  
> +AVFilterFormats *avfilter_make_format_list2(enum PixelFormat pix_fmt, ...)

any reason why this is not

AVFilterFormats *avfilter_make_format_list2(const enum PixelFormat *pix_fmt)
?

seems simpler to me, just a simple malloc+memcpy after finding the 0


8...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have often repented speaking, but never of holding my tongue.
-- Xenocrates
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