media/libmediaformatshaper/CodecSeeding.cpp

/*
 * Copyright 2021, The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//#define LOG_NDEBUG 0
#define LOG_TAG "CodecSeeding"
#include <utils/Log.h>

#include <string>

#include <media/formatshaper/CodecProperties.h>

namespace android {
namespace mediaformatshaper {

/*
 * a block of pre-loaded tunings for codecs.
 *
 * things the library seeds into the codecproperties based
 * on the mediaType.
 * XXX: parsing from a file is likely better than embedding in code.
 */
typedef struct {
    bool overrideable;
    const char *key;
    const char *value;
} preloadTuning_t;

typedef struct {
    const char *mediaType;
    preloadTuning_t *features;
} preloadTunings_t;

/*
 * 240 = 2.4 bits per pixel-per-second == 5mbps@1080, 2.3mbps@720p, which is about where
 * we want our initial floor for now.
 */

static preloadTuning_t featuresAvc[] = {
      {true, "vq-target-bpp", "2.45"},
      {true, "vq-target-qpmax", "41"},
      {true, nullptr, 0}
};

static preloadTuning_t featuresHevc[] = {
      {true, "vq-target-bpp", "2.30"},
      {true, "vq-target-qpmax", "42"}, // nop, since hevc codecs don't declare qp support
      {true, nullptr, 0}
};

static preloadTuning_t featuresGenericVideo[] = {
      {true, "vq-target-bpp", "2.40"},
      {true, nullptr, 0}
};

static preloadTunings_t preloadTunings[] = {
    { "video/avc", featuresAvc},
    { "video/hevc", &featuresHevc[0]},

    // wildcard for any video format not already captured
    { "video/*", &featuresGenericVideo[0]},

    { nullptr, nullptr}
};

void CodecProperties::addMediaDefaults(bool overrideable) {
    ALOGD("Seed: codec %s, mediatype %s, overrideable %d",
          mName.c_str(), mMediaType.c_str(), overrideable);

    // load me up with initial configuration data
    int count = 0;
    for (int i = 0; ; i++) {
        preloadTunings_t *p = &preloadTunings[i];
        if (p->mediaType == nullptr) {
            break;
        }
        bool found = false;
        if (strcmp(p->mediaType, mMediaType.c_str()) == 0) {
            found = true;
        }
        const char *r;
        if (!found && (r = strchr(p->mediaType, '*')) != NULL) {
            // wildcard; check the prefix
            size_t len = r - p->mediaType;
            if (strncmp(p->mediaType, mMediaType.c_str(), len) == 0) {
                found = true;
            }
        }

        if (!found) {
            continue;
        }
        ALOGV("seeding from mediaType '%s'", p->mediaType);

        // walk through, filling things
        if (p->features != nullptr) {
            for (int j=0;; j++) {
                preloadTuning_t *q = &p->features[j];
                if (q->key == nullptr) {
                    break;
                }
                if (q->overrideable != overrideable) {
                    continue;
                }
                setTuningValue(q->key, q->value);
                count++;
            }
            break;
        }
    }
    ALOGV("loaded %d preset values", count);
}

// a chance, as we create the codec to inject any default behaviors we want.
// XXX: consider whether we need pre/post or just post. it affects what can be
// overridden by way of the codec XML
//
void CodecProperties::Seed() {
    ALOGV("Seed: for codec %s, mediatype %s", mName.c_str(), mMediaType.c_str());
    addMediaDefaults(true);
}

void CodecProperties::Finish() {
    ALOGV("Finish: for codec %s, mediatype %s", mName.c_str(), mMediaType.c_str());
    addMediaDefaults(false);
}

} // namespace mediaformatshaper
} // namespace android