Function context_init_threaded

libswscale/utils.c:1849–1895

}

static int context_init_threaded(SwsContext *sws,
                                 SwsFilter *src_filter, SwsFilter *dst_filter)
{
    SwsInternal *c = sws_internal(sws);
    int ret;

    ret = avpriv_slicethread_create(&c->slicethread, (void*) sws,
                                    ff_sws_slice_worker, NULL, sws->threads);
    if (ret == AVERROR(ENOSYS)) {
        sws->threads = 1;
        return 0;
    } else if (ret < 0)
        return ret;

    sws->threads = ret;

    c->slice_ctx = av_calloc(sws->threads, sizeof(*c->slice_ctx));
    c->slice_err = av_calloc(sws->threads, sizeof(*c->slice_err));
    if (!c->slice_ctx || !c->slice_err)
        return AVERROR(ENOMEM);

    for (int i = 0; i < sws->threads; i++) {
        SwsContext *slice;
        slice = c->slice_ctx[i] = sws_alloc_context();
        if (!slice)
            return AVERROR(ENOMEM);
        sws_internal(slice)->parent = sws;
        c->nb_slice_ctx++;

        ret = av_opt_copy(slice, sws);
        if (ret < 0)
            return ret;
        slice->threads = 1;

        ret = ff_sws_init_single_context(slice, src_filter, dst_filter);
        if (ret < 0)
            return ret;

        if (slice->dither == SWS_DITHER_ED) {
            av_log(c, AV_LOG_VERBOSE,
                   "Error-diffusion dither is in use, scaling will be single-threaded.");
            break;
        }
    }

    return 0;
}

av_cold int sws_init_context(SwsContext *sws, SwsFilter *srcFilter,
                             SwsFilter *dstFilter)