// main entry point
int VP8EncAnalyze(VP8Encoder* const enc) {
int ok = 1;
const int do_segments =
enc->config_->emulate_jpeg_size || // We need the complexity evaluation.
(enc->segment_hdr_.num_segments_ > 1) ||
(enc->method_ == 0); // for method 0, we need preds_[] to be filled.
if (do_segments) {
const int last_row = enc->mb_h_;
// We give a little more than a half work to the main thread.
const int split_row = (9 * last_row + 15) >> 4;
const int total_mb = last_row * enc->mb_w_;
#ifdef WEBP_USE_THREAD
const int kMinSplitRow = 2; // minimal rows needed for mt to be worth it
const int do_mt = (enc->thread_level_ > 0) && (split_row >= kMinSplitRow);
#else
const int do_mt = 0;
#endif
SegmentJob main_job;
if (do_mt) {
SegmentJob side_job;
// Note the use of '&' instead of '&&' because we must call the functions
// no matter what.
InitSegmentJob(enc, &main_job, 0, split_row);
InitSegmentJob(enc, &side_job, split_row, last_row);
// we don't need to call Reset() on main_job.worker, since we're calling
// WebPWorkerExecute() on it
ok &= WebPWorkerReset(&side_job.worker);
// launch the two jobs in parallel
if (ok) {
WebPWorkerLaunch(&side_job.worker);
WebPWorkerExecute(&main_job.worker);
ok &= WebPWorkerSync(&side_job.worker);
ok &= WebPWorkerSync(&main_job.worker);
}
WebPWorkerEnd(&side_job.worker);
if (ok) MergeJobs(&side_job, &main_job); // merge results together
} else {
// Even for single-thread case, we use the generic Worker tools.
InitSegmentJob(enc, &main_job, 0, last_row);
WebPWorkerExecute(&main_job.worker);
ok &= WebPWorkerSync(&main_job.worker);
}
WebPWorkerEnd(&main_job.worker);
if (ok) {
enc->alpha_ = main_job.alpha / total_mb;
enc->uv_alpha_ = main_job.uv_alpha / total_mb;
AssignSegments(enc, main_job.alphas);
}
} else { // Use only one default segment.
int VP8EncStartAlpha(VP8Encoder* const enc) {
if (enc->has_alpha_) {
if (enc->thread_level_ > 0) {
WebPWorker* const worker = &enc->alpha_worker_;
if (!WebPWorkerReset(worker)) { // Makes sure worker is good to go.
return 0;
}
WebPWorkerLaunch(worker);
return 1;
} else {
return CompressAlphaJob(enc, NULL); // just do the job right away
}
}
return 1;
}
