[FFmpeg-devel] [PATCH 6/6] lavc/flacdsp: document limitations of the LPC encoder

Michael Niedermayer michaelni at gmx.at
Wed Aug 13 04:50:25 CEST 2014


On Tue, Aug 12, 2014 at 11:22:07PM +0200, James Darnley wrote:
> ---
>  libavcodec/flacdsp.h |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/libavcodec/flacdsp.h b/libavcodec/flacdsp.h
> index 272cf2a..36cd904 100644
> --- a/libavcodec/flacdsp.h
> +++ b/libavcodec/flacdsp.h
> @@ -27,6 +27,13 @@ typedef struct FLACDSPContext {
>                             int len, int shift);
>      void (*lpc)(int32_t *samples, const int coeffs[32], int order,
>                  int qlevel, int len);
> +    /**
> +     * This function has some limitations with various configurations:
> +     * - when CONFIG_SMALL is 0 there is an unrolled loop which assumes the
> +     *   maximum value of order is 32.
> +     * - when SSE4 (or newer) is available on x86 there is an unrolled copy
> +     *   which also assumes the maximum value of order is 0.
> +     */

sounds like

printf()
on fridays with SSE4 this is limited to 27 characters

a function either should have a limit or not have one, it should
not depend on other factors

People using this function must be able to tell in what cases they
can use it

and People optimizing the function need to know which cases their
optimized code must support

the API defines both

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

During times of universal deceit, telling the truth becomes a
revolutionary act. -- George Orwell
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 181 bytes
Desc: Digital signature
URL: <https://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20140813/75af2abe/attachment.asc>


More information about the ffmpeg-devel mailing list