From 5a65a6e22017e51ebcebb0f41510c54f1085f82c Mon Sep 17 00:00:00 2001 From: Andreas Huber Date: Tue, 8 Sep 2009 16:07:15 -0700 Subject: Added a .amr file extractor (for AMR-NB and AMR-WB content). --- media/libstagefright/AMRExtractor.cpp | 238 ++++++++++++++++++++++++++++++++++ 1 file changed, 238 insertions(+) create mode 100644 media/libstagefright/AMRExtractor.cpp (limited to 'media/libstagefright/AMRExtractor.cpp') diff --git a/media/libstagefright/AMRExtractor.cpp b/media/libstagefright/AMRExtractor.cpp new file mode 100644 index 0000000..4772aca --- /dev/null +++ b/media/libstagefright/AMRExtractor.cpp @@ -0,0 +1,238 @@ +/* + * Copyright (C) 2009 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 "AMRExtractor" +#include + +#include +#include +#include +#include +#include +#include +#include +#include + +namespace android { + +class AMRSource : public MediaSource { +public: + AMRSource(const sp &source, bool isWide); + + virtual status_t start(MetaData *params = NULL); + virtual status_t stop(); + + virtual sp getFormat(); + + virtual status_t read( + MediaBuffer **buffer, const ReadOptions *options = NULL); + +protected: + virtual ~AMRSource(); + +private: + sp mDataSource; + bool mIsWide; + + off_t mOffset; + int64_t mCurrentTimeUs; + bool mStarted; + MediaBufferGroup *mGroup; + + AMRSource(const AMRSource &); + AMRSource &operator=(const AMRSource &); +}; + +//////////////////////////////////////////////////////////////////////////////// + +AMRExtractor::AMRExtractor(const sp &source) + : mDataSource(source), + mInitCheck(NO_INIT) { + String8 mimeType; + float confidence; + if (SniffAMR(mDataSource, &mimeType, &confidence)) { + mInitCheck = OK; + mIsWide = (mimeType == "audio/amr-wb"); + } +} + +AMRExtractor::~AMRExtractor() { +} + +size_t AMRExtractor::countTracks() { + return mInitCheck == OK ? 1 : 0; +} + +sp AMRExtractor::getTrack(size_t index) { + if (mInitCheck != OK || index != 0) { + return NULL; + } + + return new AMRSource(mDataSource, mIsWide); +} + +sp AMRExtractor::getTrackMetaData(size_t index) { + if (mInitCheck != OK || index != 0) { + return NULL; + } + + return makeAMRFormat(mIsWide); +} + +// static +sp AMRExtractor::makeAMRFormat(bool isWide) { + sp meta = new MetaData; + meta->setCString(kKeyMIMEType, isWide ? "audio/amr-wb" : "audio/3gpp"); + meta->setInt32(kKeyChannelCount, 1); + meta->setInt32(kKeySampleRate, isWide ? 16000 : 8000); + + return meta; +} + +//////////////////////////////////////////////////////////////////////////////// + +AMRSource::AMRSource(const sp &source, bool isWide) + : mDataSource(source), + mIsWide(isWide), + mOffset(mIsWide ? 9 : 6), + mCurrentTimeUs(0), + mStarted(false), + mGroup(NULL) { +} + +AMRSource::~AMRSource() { + if (mStarted) { + stop(); + } +} + +status_t AMRSource::start(MetaData *params) { + CHECK(!mStarted); + + mOffset = mIsWide ? 9 : 6; + mCurrentTimeUs = 0; + mGroup = new MediaBufferGroup; + mGroup->add_buffer(new MediaBuffer(128)); + mStarted = true; + + return OK; +} + +status_t AMRSource::stop() { + CHECK(mStarted); + + delete mGroup; + mGroup = NULL; + + mStarted = false; + return OK; +} + +sp AMRSource::getFormat() { + return AMRExtractor::makeAMRFormat(mIsWide); +} + +status_t AMRSource::read( + MediaBuffer **out, const ReadOptions *options) { + *out = NULL; + + uint8_t header; + ssize_t n = mDataSource->read_at(mOffset, &header, 1); + + if (n < 1) { + return ERROR_IO; + } + + MediaBuffer *buffer; + status_t err = mGroup->acquire_buffer(&buffer); + if (err != OK) { + return err; + } + + if (header & 0x83) { + // Padding bits must be 0. + + return ERROR_MALFORMED; + } + + unsigned FT = (header >> 3) & 0x0f; + + if (FT > 8 || (!mIsWide && FT > 7)) { + return ERROR_MALFORMED; + } + + static const size_t kFrameSizeNB[8] = { + 95, 103, 118, 134, 148, 159, 204, 244 + }; + static const size_t kFrameSizeWB[9] = { + 132, 177, 253, 285, 317, 365, 397, 461, 477 + }; + + size_t frameSize = mIsWide ? kFrameSizeWB[FT] : kFrameSizeNB[FT]; + + // Round up bits to bytes and add 1 for the header byte. + frameSize = (frameSize + 7) / 8 + 1; + + n = mDataSource->read_at(mOffset, buffer->data(), frameSize); + + if (n != (ssize_t)frameSize) { + buffer->release(); + buffer = NULL; + + return ERROR_IO; + } + + buffer->set_range(0, frameSize); + buffer->meta_data()->setInt32( + kKeyTimeUnits, (mCurrentTimeUs + 500) / 1000); + buffer->meta_data()->setInt32( + kKeyTimeScale, 1000); + + mOffset += frameSize; + mCurrentTimeUs += 20000; // Each frame is 20ms + + *out = buffer; + + return OK; +} + +//////////////////////////////////////////////////////////////////////////////// + +bool SniffAMR( + const sp &source, String8 *mimeType, float *confidence) { + char header[9]; + + if (source->read_at(0, header, sizeof(header)) != sizeof(header)) { + return false; + } + + if (!memcmp(header, "#!AMR\n", 6)) { + *mimeType = "audio/3gpp"; + *confidence = 0.5; + + return true; + } else if (!memcmp(header, "#!AMR-WB\n", 9)) { + *mimeType = "audio/amr-wb"; + *confidence = 0.5; + + return true; + } + + return false; +} + +} // namespace android -- cgit v1.1