[FFmpeg-devel] [PATCH] Fix linesize computation for NV formats

Ramiro Polla ramiro.polla
Wed Nov 25 18:24:03 CET 2009


On Tue, Nov 24, 2009 at 12:27 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Fri, Nov 20, 2009 at 02:16:44PM -0200, Ramiro Polla wrote:
>> On Fri, Nov 20, 2009 at 9:56 AM, Ramiro Polla <ramiro.polla at gmail.com> wrote:
>> > On Thu, Nov 19, 2009 at 10:54 PM, Ramiro Polla <ramiro.polla at gmail.com> wrote:
>> >> On Thu, Nov 19, 2009 at 10:38 PM, Stefano Sabatini
>> >> <stefano.sabatini-lala at poste.it> wrote:
>> >>> On date Thursday 2009-11-19 17:51:30 +0100, Michael Niedermayer encoded:
>> >>>> On Thu, Nov 19, 2009 at 01:37:03AM +0100, Stefano Sabatini wrote:
>> >>> [...]
>> >>>> > So basically all the code affected by the change is indeed code which
>> >>>> > is never used, my patch simply makes the linesize params semantics for
>> >>>> > NV formats consistent with that of all the other formats (thus
>> >>>> > simplifying the code if we choose to use pixdesc for ff_fill_XXX).
>> >>>>
>> >>>> if no code uses NV12 it should be removed (i dont belive this though)
>> >>>> if any code uses NV12 your patch will break it.
>> >>>
>> >>> ffmpeg doesn't support NV12 as input, but can convert to NV12 /
>> >>> NV21. So we can create a stream with pix_fmt nv12 but there is no mean
>> >>> to visually test it (e.g. with ffplay) or convert it back to a stream
>> >>> which is playable by ffmpeg, but maybe someone can suggest some way to
>> >>> display such a format e.g. with mplayer or vlc.
>> >>>
>> >>> Also I wonder how hard would be to add it as an input format in lsws.
>> >>
>> >> I have a device with a hardware decoder to nv12 that also displays in
>> >> nv12 at work. I might take a look tomorrow if I manage to find some
>> >> time...
>> >
>> > One more change was needed to get raw nv12 output properly. With
>> > attached patch I can
>> > ./ffmpeg_g -i input.avi -s 1280x720 -pix_fmt nv12 -f rawvideo -y output.nv12
>> > and then feed output.nv12 to the display frame by frame.
>> >
>> > I haven't worked on nv12 support as input to swscale yet. I'll do it
>> > either this afternoon or in two weeks =)
>>
>> And here is a patch to take nv12 and nv21 as input for swscale
>> (depends on the previous patch).
>>
>> Ramiro Polla
>
>> ?swscale.c ? ? ? ? ?| ? ?2 ++
>> ?swscale_template.c | ? 23 +++++++++++++++++++++++
>> ?2 files changed, 25 insertions(+)
>> 7e95c118694ad7ee4d89e948fea7e3252238d5d9 ?nv12in.diff
>> Index: libswscale/swscale.c
>> ===================================================================
>> --- libswscale/swscale.c ? ? ?(revis?o 29937)
>> +++ libswscale/swscale.c ? ? ?(c?pia de trabalho)
>> @@ -134,6 +134,8 @@
>> ? ? ? ? ?|| (x)==PIX_FMT_GRAY8 ? ? ? \
>> ? ? ? ? ?|| (x)==PIX_FMT_YUV410P ? ? \
>> ? ? ? ? ?|| (x)==PIX_FMT_YUV440P ? ? \
>> + ? ? ? ?|| (x)==PIX_FMT_NV12 ? ? ? ?\
>> + ? ? ? ?|| (x)==PIX_FMT_NV21 ? ? ? ?\
>> ? ? ? ? ?|| (x)==PIX_FMT_GRAY16BE ? ?\
>> ? ? ? ? ?|| (x)==PIX_FMT_GRAY16LE ? ?\
>> ? ? ? ? ?|| (x)==PIX_FMT_YUV444P ? ? \
>> Index: libswscale/swscale_template.c
>> ===================================================================
>> --- libswscale/swscale_template.c ? ? (revis?o 29937)
>> +++ libswscale/swscale_template.c ? ? (c?pia de trabalho)
>> @@ -1784,6 +1784,27 @@
>> ?#endif
>> ?}
>>
>> +#define NVxxToUV(U, V) ? ? ? ? ? ? ?\
>> + ? ?int i; ? ? ? ? ? ? ? ? ? ? ? ? ?\
>> + ? ?for (i = 0; i < width; i++) { ? \
>> + ? ? ? ?dstU[i]= src1[2*i+U]; ? ? ? \
>> + ? ? ? ?dstV[i]= src1[2*i+V]; ? ? ? \
>> + ? ?} ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
>> +
>> +static inline void RENAME(nv12ToUV)(uint8_t *dstU, uint8_t *dstV,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?const uint8_t *src1, const uint8_t *src2,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?long width, uint32_t *unused)
>> +{
>> + ? ?NVxxToUV(0, 1);
>> +}
>> +
>> +static inline void RENAME(nv21ToUV)(uint8_t *dstU, uint8_t *dstV,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?const uint8_t *src1, const uint8_t *src2,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?long width, uint32_t *unused)
>> +{
>> + ? ?NVxxToUV(1, 0);
>> +}
>
> you need just 1 function, just exchange the 2 dst pointers

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