utils.c

        for (i = 0; i < c->vLumBufSize; i++)
            av_freep(&c->lumPixBuf[i]);
        av_freep(&c->lumPixBuf);
    }

    if (c->chrUPixBuf) {
        for (i = 0; i < c->vChrBufSize; i++)
            av_freep(&c->chrUPixBuf[i]);
        av_freep(&c->chrUPixBuf);
        av_freep(&c->chrVPixBuf);
    }

    if (CONFIG_SWSCALE_ALPHA && c->alpPixBuf) {
        for (i = 0; i < c->vLumBufSize; i++)
            av_freep(&c->alpPixBuf[i]);
        av_freep(&c->alpPixBuf);
    }

    for (i = 0; i < 4; i++)
        av_freep(&c->dither_error[i]);

    av_freep(&c->vLumFilter);
    av_freep(&c->vChrFilter);
    av_freep(&c->hLumFilter);
    av_freep(&c->hChrFilter);
#if HAVE_ALTIVEC
    av_freep(&c->vYCoeffsBank);
    av_freep(&c->vCCoeffsBank);
#endif

    av_freep(&c->vLumFilterPos);
    av_freep(&c->vChrFilterPos);
    av_freep(&c->hLumFilterPos);
    av_freep(&c->hChrFilterPos);

#if HAVE_MMX_INLINE
#if USE_MMAP
    if (c->lumMmxextFilterCode)
        munmap(c->lumMmxextFilterCode, c->lumMmxextFilterCodeSize);
    if (c->chrMmxextFilterCode)
        munmap(c->chrMmxextFilterCode, c->chrMmxextFilterCodeSize);
#elif HAVE_VIRTUALALLOC
    if (c->lumMmxextFilterCode)
        VirtualFree(c->lumMmxextFilterCode, 0, MEM_RELEASE);
    if (c->chrMmxextFilterCode)
        VirtualFree(c->chrMmxextFilterCode, 0, MEM_RELEASE);
#else
    av_free(c->lumMmxextFilterCode);
    av_free(c->chrMmxextFilterCode);
#endif
    c->lumMmxextFilterCode = NULL;
    c->chrMmxextFilterCode = NULL;
#endif /* HAVE_MMX_INLINE */

    av_freep(&c->yuvTable);
    av_freep(&c->formatConvBuffer);

    av_free(c);
}

struct SwsContext *sws_getCachedContext(struct SwsContext *context, int srcW,
                                        int srcH, enum AVPixelFormat srcFormat,
                                        int dstW, int dstH,
                                        enum AVPixelFormat dstFormat, int flags,
                                        SwsFilter *srcFilter,
                                        SwsFilter *dstFilter,
                                        const double *param)
{
    static const double default_param[2] = { SWS_PARAM_DEFAULT,
                                             SWS_PARAM_DEFAULT };

    if (!param)
        param = default_param;

    if (context &&
        (context->srcW      != srcW      ||
         context->srcH      != srcH      ||
         context->srcFormat != srcFormat ||
         context->dstW      != dstW      ||
         context->dstH      != dstH      ||
         context->dstFormat != dstFormat ||
         context->flags     != flags     ||
         context->param[0]  != param[0]  ||
         context->param[1]  != param[1])) {
        sws_freeContext(context);
        context = NULL;
    }

    if (!context) {
        if (!(context = sws_alloc_context()))
            return NULL;
        context->srcW      = srcW;
        context->srcH      = srcH;
        context->srcFormat = srcFormat;
        context->dstW      = dstW;
        context->dstH      = dstH;
        context->dstFormat = dstFormat;
        context->flags     = flags;
        context->param[0]  = param[0];
        context->param[1]  = param[1];
        if (sws_init_context(context, srcFilter, dstFilter) < 0) {
            sws_freeContext(context);
            return NULL;
        }
    }
    return context;
}