vlc functions.

picture_CopyPixels.c

void picture_CopyPixels( picture_t *p_dst, const picture_t *p_src )
{
    for( int i = 0; i < p_src->i_planes ; i++ )
        plane_CopyPixels( p_dst->p+i, p_src->p+i );

    assert( p_dst->context == NULL );

    if( p_src->context != NULL )
        p_dst->context = p_src->context->copy( p_src->context );
}

void picture_Copy( picture_t *p_dst, const picture_t *p_src )
{
    picture_CopyPixels( p_dst, p_src );
    picture_CopyProperties( p_dst, p_src );
}

picture_UpdatePlanes.c

int picture_UpdatePlanes(picture_t *picture, uint8_t *data, unsigned pitch)
{
    /* fill in buffer info in first plane */
    picture->p->p_pixels = data;
    picture->p->i_pitch  = pitch;
    picture->p->i_lines  = picture->format.i_height;
    assert(picture->p->i_visible_pitch <= picture->p->i_pitch);
    assert(picture->p->i_visible_lines <= picture->p->i_lines);

    /*  Fill chroma planes for biplanar YUV */
    if (picture->format.i_chroma == VLC_CODEC_NV12 ||
        picture->format.i_chroma == VLC_CODEC_NV21 ||
        picture->format.i_chroma == VLC_CODEC_P010) {

        for (int n = 1; n < picture->i_planes; n++) {
            const plane_t *o = &picture->p[n-1];
            plane_t *p = &picture->p[n];

            p->p_pixels = o->p_pixels + o->i_lines * o->i_pitch;
            p->i_pitch  = pitch;
            p->i_lines  = picture->format.i_height / 2;
            assert(p->i_visible_pitch <= p->i_pitch);
            assert(p->i_visible_lines <= p->i_lines);
        }
        /* The dx/d3d buffer is always allocated as NV12 */
        if (vlc_fourcc_AreUVPlanesSwapped(picture->format.i_chroma, VLC_CODEC_NV12)) {
            /* TODO : Swap NV21 UV planes to match NV12 */
            return VLC_EGENERIC;
        }
    }

    /*  Fill chroma planes for planar YUV */
    else
    if (picture->format.i_chroma == VLC_CODEC_I420 ||
        picture->format.i_chroma == VLC_CODEC_J420 ||
        picture->format.i_chroma == VLC_CODEC_YV12) {

        for (int n = 1; n < picture->i_planes; n++) {
            const plane_t *o = &picture->p[n-1];
            plane_t *p = &picture->p[n];

            p->p_pixels = o->p_pixels + o->i_lines * o->i_pitch;
            p->i_pitch  = pitch / 2;
            p->i_lines  = picture->format.i_height / 2;
        }
        /* The dx/d3d buffer is always allocated as YV12 */
        if (vlc_fourcc_AreUVPlanesSwapped(picture->format.i_chroma, VLC_CODEC_YV12))
            picture_SwapUV( picture );
    }
    return VLC_SUCCESS;
}

plane_CopyPixels.c

void plane_CopyPixels( plane_t *p_dst, const plane_t *p_src )
{
    const unsigned i_width  = __MIN( p_dst->i_visible_pitch,
                                     p_src->i_visible_pitch );
    const unsigned i_height = __MIN( p_dst->i_visible_lines,
                                     p_src->i_visible_lines );

    /* The 2x visible pitch check does two things:
       1) Makes field plane_t's work correctly (see the deinterlacer module)
       2) Moves less data if the pitch and visible pitch differ much.
    */
    if( p_src->i_pitch == p_dst->i_pitch  &&
        p_src->i_pitch < 2*p_src->i_visible_pitch )
    {
        /* There are margins, but with the same width : perfect ! */
        memcpy( p_dst->p_pixels, p_src->p_pixels,
                    p_src->i_pitch * i_height );
    }
    else
    {
        /* We need to proceed line by line */
        uint8_t *p_in = p_src->p_pixels;
        uint8_t *p_out = p_dst->p_pixels;

        assert( p_in );
        assert( p_out );

        for( int i_line = i_height; i_line--; )
        {
            memcpy( p_out, p_in, i_width );
            p_in += p_src->i_pitch;
            p_out += p_dst->i_pitch;
        }
    }
}