[FFmpeg-devel] [PATCH] Fix non-mod16 libtheora encoding

Michael Niedermayer michaelni
Fri May 22 04:15:58 CEST 2009


On Thu, May 21, 2009 at 05:04:00PM -0700, Baptiste Coudurier wrote:
> David Conrad wrote:
> > On May 21, 2009, at 6:14 PM, Baptiste Coudurier wrote:
> > 
> >> Hi,
> >>
> >> David Conrad wrote:
> >>> Hi,
> >>>
> >>> Currently using non-mod16 sizes produces garbage.
> >>>
> >>>
> >>> ------------------------------------------------------------------------
> >>>
> >>> commit 7af4d351600878e1c37467837d8d10c226e2b805
> >>> Author: David Conrad <lessen42 at gmail.com>
> >>> Date:   Thu May 21 17:38:44 2009 -0400
> >>>
> >>>    Fix libtheora encoding for non-mod16 sizes
> >>>
> >>> diff --git a/libavcodec/libtheoraenc.c b/libavcodec/libtheoraenc.c
> >>> index dbc98e3..ef8b6aa 100644
> >>> --- a/libavcodec/libtheoraenc.c
> >>> +++ b/libavcodec/libtheoraenc.c
> >>> @@ -87,12 +87,12 @@ static av_cold int encode_init(AVCodecContext*
> >>> avc_context)
> >>>
> >>>     /* Set up the theora_info struct */
> >>>     theora_info_init( &t_info );
> >>> -    t_info.width = avc_context->width;
> >>> -    t_info.height = avc_context->height;
> >>> +    t_info.width = (avc_context->width + 15) & 0xFFFFFFF0;
> >>> +    t_info.height = (avc_context->height + 15) & 0xFFFFFFF0;
> >>>     t_info.frame_width = avc_context->width;
> >>>     t_info.frame_height = avc_context->height;
> >>>     t_info.offset_x = 0;
> >>> -    t_info.offset_y = 0;
> >>> +    t_info.offset_y = avc_context->height & 0xf;
> >>>     /* Swap numerator and denominator as time_base in AVCodecContext
> >>> gives the
> >>>      * time period between frames, but theora_info needs the
> >>> framerate.  */
> >>>     t_info.fps_numerator = avc_context->time_base.den;
> >>> @@ -186,8 +186,8 @@ static int encode_frame(
> >>>         return -1;
> >>>     }
> >>>
> >>> -    t_yuv_buffer.y_width = avc_context->width;
> >>> -    t_yuv_buffer.y_height = avc_context->height;
> >>> +    t_yuv_buffer.y_width = (avc_context->width + 15) & 0xFFFFFFF0;
> >>> +    t_yuv_buffer.y_height = (avc_context->height + 15) & 0xFFFFFFF0;
> >>>     t_yuv_buffer.y_stride = frame->linesize[0];
> >>>     t_yuv_buffer.uv_width = t_yuv_buffer.y_width / 2;
> >>>     t_yuv_buffer.uv_height = t_yuv_buffer.y_height / 2;
> >>
> >> I believe a failure is more appropriate and a message saying that
> >> libtheora does not support non mod 16 width/height.
> > 
> > Why not simply do the little bit of work libtheora won't do?
> 
> Because acting on behalf of the user is bad.
> 
> Inform the user of the problem, and let him handle it by either pad or crop
> as he wishes, is far better IMHO.

if libtheora doesnt support non mod 16 then yes i fully agree that we should
fail rather than clip something at random behind the users back

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you really think that XML is the answer, then you definitly missunderstood
the question -- Attila Kinali
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