| /* |
| * Copyright (C) 2010 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 "avc_utils" |
| #include <utils/Log.h> |
| |
| #include "include/avc_utils.h" |
| |
| #include <media/stagefright/foundation/ABitReader.h> |
| #include <media/stagefright/foundation/ADebug.h> |
| #include <media/stagefright/foundation/hexdump.h> |
| #include <media/stagefright/MediaDefs.h> |
| #include <media/stagefright/MediaErrors.h> |
| #include <media/stagefright/MetaData.h> |
| #include <utils/misc.h> |
| |
| namespace android { |
| |
| unsigned parseUE(ABitReader *br) { |
| unsigned numZeroes = 0; |
| while (br->getBits(1) == 0) { |
| ++numZeroes; |
| } |
| |
| unsigned x = br->getBits(numZeroes); |
| |
| return x + (1u << numZeroes) - 1; |
| } |
| |
| unsigned parseUEWithFallback(ABitReader *br, unsigned fallback) { |
| unsigned numZeroes = 0; |
| while (br->getBitsWithFallback(1, 1) == 0) { |
| ++numZeroes; |
| } |
| uint32_t x; |
| if (numZeroes < 32) { |
| if (br->getBitsGraceful(numZeroes, &x)) { |
| return x + (1u << numZeroes) - 1; |
| } else { |
| return fallback; |
| } |
| } else { |
| br->skipBits(numZeroes); |
| return fallback; |
| } |
| } |
| |
| signed parseSE(ABitReader *br) { |
| unsigned codeNum = parseUE(br); |
| |
| return (codeNum & 1) ? (codeNum + 1) / 2 : -signed(codeNum / 2); |
| } |
| |
| signed parseSEWithFallback(ABitReader *br, signed fallback) { |
| // NOTE: parseUE cannot normally return ~0 as the max supported value is 0xFFFE |
| unsigned codeNum = parseUEWithFallback(br, ~0U); |
| if (codeNum == ~0U) { |
| return fallback; |
| } |
| return (codeNum & 1) ? (codeNum + 1) / 2 : -signed(codeNum / 2); |
| } |
| |
| static void skipScalingList(ABitReader *br, size_t sizeOfScalingList) { |
| size_t lastScale = 8; |
| size_t nextScale = 8; |
| for (size_t j = 0; j < sizeOfScalingList; ++j) { |
| if (nextScale != 0) { |
| signed delta_scale = parseSE(br); |
| // ISO_IEC_14496-10_201402-ITU, 7.4.2.1.1.1, The value of delta_scale |
| // shall be in the range of −128 to +127, inclusive. |
| if (delta_scale < -128) { |
| ALOGW("delta_scale (%d) is below range, capped to -128", delta_scale); |
| delta_scale = -128; |
| } else if (delta_scale > 127) { |
| ALOGW("delta_scale (%d) is above range, capped to 127", delta_scale); |
| delta_scale = 127; |
| } |
| nextScale = (lastScale + (delta_scale + 256)) % 256; |
| } |
| |
| lastScale = (nextScale == 0) ? lastScale : nextScale; |
| } |
| } |
| |
| // Determine video dimensions from the sequence parameterset. |
| void FindAVCDimensions( |
| const sp<ABuffer> &seqParamSet, |
| int32_t *width, int32_t *height, |
| int32_t *sarWidth, int32_t *sarHeight) { |
| ABitReader br(seqParamSet->data() + 1, seqParamSet->size() - 1); |
| |
| unsigned profile_idc = br.getBits(8); |
| br.skipBits(16); |
| parseUE(&br); // seq_parameter_set_id |
| |
| unsigned chroma_format_idc = 1; // 4:2:0 chroma format |
| |
| if (profile_idc == 100 || profile_idc == 110 |
| || profile_idc == 122 || profile_idc == 244 |
| || profile_idc == 44 || profile_idc == 83 || profile_idc == 86) { |
| chroma_format_idc = parseUE(&br); |
| if (chroma_format_idc == 3) { |
| br.skipBits(1); // residual_colour_transform_flag |
| } |
| parseUE(&br); // bit_depth_luma_minus8 |
| parseUE(&br); // bit_depth_chroma_minus8 |
| br.skipBits(1); // qpprime_y_zero_transform_bypass_flag |
| |
| if (br.getBits(1)) { // seq_scaling_matrix_present_flag |
| for (size_t i = 0; i < 8; ++i) { |
| if (br.getBits(1)) { // seq_scaling_list_present_flag[i] |
| |
| // WARNING: the code below has not ever been exercised... |
| // need a real-world example. |
| |
| if (i < 6) { |
| // ScalingList4x4[i],16,... |
| skipScalingList(&br, 16); |
| } else { |
| // ScalingList8x8[i-6],64,... |
| skipScalingList(&br, 64); |
| } |
| } |
| } |
| } |
| } |
| |
| parseUE(&br); // log2_max_frame_num_minus4 |
| unsigned pic_order_cnt_type = parseUE(&br); |
| |
| if (pic_order_cnt_type == 0) { |
| parseUE(&br); // log2_max_pic_order_cnt_lsb_minus4 |
| } else if (pic_order_cnt_type == 1) { |
| // offset_for_non_ref_pic, offset_for_top_to_bottom_field and |
| // offset_for_ref_frame are technically se(v), but since we are |
| // just skipping over them the midpoint does not matter. |
| |
| br.getBits(1); // delta_pic_order_always_zero_flag |
| parseUE(&br); // offset_for_non_ref_pic |
| parseUE(&br); // offset_for_top_to_bottom_field |
| |
| unsigned num_ref_frames_in_pic_order_cnt_cycle = parseUE(&br); |
| for (unsigned i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; ++i) { |
| parseUE(&br); // offset_for_ref_frame |
| } |
| } |
| |
| parseUE(&br); // num_ref_frames |
| br.getBits(1); // gaps_in_frame_num_value_allowed_flag |
| |
| unsigned pic_width_in_mbs_minus1 = parseUE(&br); |
| unsigned pic_height_in_map_units_minus1 = parseUE(&br); |
| unsigned frame_mbs_only_flag = br.getBits(1); |
| |
| *width = pic_width_in_mbs_minus1 * 16 + 16; |
| |
| *height = (2 - frame_mbs_only_flag) |
| * (pic_height_in_map_units_minus1 * 16 + 16); |
| |
| if (!frame_mbs_only_flag) { |
| br.getBits(1); // mb_adaptive_frame_field_flag |
| } |
| |
| br.getBits(1); // direct_8x8_inference_flag |
| |
| if (br.getBits(1)) { // frame_cropping_flag |
| unsigned frame_crop_left_offset = parseUE(&br); |
| unsigned frame_crop_right_offset = parseUE(&br); |
| unsigned frame_crop_top_offset = parseUE(&br); |
| unsigned frame_crop_bottom_offset = parseUE(&br); |
| |
| unsigned cropUnitX, cropUnitY; |
| if (chroma_format_idc == 0 /* monochrome */) { |
| cropUnitX = 1; |
| cropUnitY = 2 - frame_mbs_only_flag; |
| } else { |
| unsigned subWidthC = (chroma_format_idc == 3) ? 1 : 2; |
| unsigned subHeightC = (chroma_format_idc == 1) ? 2 : 1; |
| |
| cropUnitX = subWidthC; |
| cropUnitY = subHeightC * (2 - frame_mbs_only_flag); |
| } |
| |
| ALOGV("frame_crop = (%u, %u, %u, %u), cropUnitX = %u, cropUnitY = %u", |
| frame_crop_left_offset, frame_crop_right_offset, |
| frame_crop_top_offset, frame_crop_bottom_offset, |
| cropUnitX, cropUnitY); |
| |
| *width -= |
| (frame_crop_left_offset + frame_crop_right_offset) * cropUnitX; |
| *height -= |
| (frame_crop_top_offset + frame_crop_bottom_offset) * cropUnitY; |
| } |
| |
| if (sarWidth != NULL) { |
| *sarWidth = 0; |
| } |
| |
| if (sarHeight != NULL) { |
| *sarHeight = 0; |
| } |
| |
| if (br.getBits(1)) { // vui_parameters_present_flag |
| unsigned sar_width = 0, sar_height = 0; |
| |
| if (br.getBits(1)) { // aspect_ratio_info_present_flag |
| unsigned aspect_ratio_idc = br.getBits(8); |
| |
| if (aspect_ratio_idc == 255 /* extendedSAR */) { |
| sar_width = br.getBits(16); |
| sar_height = br.getBits(16); |
| } else { |
| static const struct { unsigned width, height; } kFixedSARs[] = { |
| { 0, 0 }, // Invalid |
| { 1, 1 }, |
| { 12, 11 }, |
| { 10, 11 }, |
| { 16, 11 }, |
| { 40, 33 }, |
| { 24, 11 }, |
| { 20, 11 }, |
| { 32, 11 }, |
| { 80, 33 }, |
| { 18, 11 }, |
| { 15, 11 }, |
| { 64, 33 }, |
| { 160, 99 }, |
| { 4, 3 }, |
| { 3, 2 }, |
| { 2, 1 }, |
| }; |
| |
| if (aspect_ratio_idc > 0 && aspect_ratio_idc < NELEM(kFixedSARs)) { |
| sar_width = kFixedSARs[aspect_ratio_idc].width; |
| sar_height = kFixedSARs[aspect_ratio_idc].height; |
| } |
| } |
| } |
| |
| ALOGV("sample aspect ratio = %u : %u", sar_width, sar_height); |
| |
| if (sarWidth != NULL) { |
| *sarWidth = sar_width; |
| } |
| |
| if (sarHeight != NULL) { |
| *sarHeight = sar_height; |
| } |
| } |
| } |
| |
| status_t getNextNALUnit( |
| const uint8_t **_data, size_t *_size, |
| const uint8_t **nalStart, size_t *nalSize, |
| bool startCodeFollows) { |
| const uint8_t *data = *_data; |
| size_t size = *_size; |
| |
| *nalStart = NULL; |
| *nalSize = 0; |
| |
| if (size < 3) { |
| return -EAGAIN; |
| } |
| |
| size_t offset = 0; |
| |
| // A valid startcode consists of at least two 0x00 bytes followed by 0x01. |
| for (; offset + 2 < size; ++offset) { |
| if (data[offset + 2] == 0x01 && data[offset] == 0x00 |
| && data[offset + 1] == 0x00) { |
| break; |
| } |
| } |
| if (offset + 2 >= size) { |
| *_data = &data[offset]; |
| *_size = 2; |
| return -EAGAIN; |
| } |
| offset += 3; |
| |
| size_t startOffset = offset; |
| |
| for (;;) { |
| while (offset < size && data[offset] != 0x01) { |
| ++offset; |
| } |
| |
| if (offset == size) { |
| if (startCodeFollows) { |
| offset = size + 2; |
| break; |
| } |
| |
| return -EAGAIN; |
| } |
| |
| if (data[offset - 1] == 0x00 && data[offset - 2] == 0x00) { |
| break; |
| } |
| |
| ++offset; |
| } |
| |
| size_t endOffset = offset - 2; |
| while (endOffset > startOffset + 1 && data[endOffset - 1] == 0x00) { |
| --endOffset; |
| } |
| |
| *nalStart = &data[startOffset]; |
| *nalSize = endOffset - startOffset; |
| |
| if (offset + 2 < size) { |
| *_data = &data[offset - 2]; |
| *_size = size - offset + 2; |
| } else { |
| *_data = NULL; |
| *_size = 0; |
| } |
| |
| return OK; |
| } |
| |
| static sp<ABuffer> FindNAL(const uint8_t *data, size_t size, unsigned nalType) { |
| const uint8_t *nalStart; |
| size_t nalSize; |
| while (getNextNALUnit(&data, &size, &nalStart, &nalSize, true) == OK) { |
| if (nalSize > 0 && (nalStart[0] & 0x1f) == nalType) { |
| sp<ABuffer> buffer = new ABuffer(nalSize); |
| memcpy(buffer->data(), nalStart, nalSize); |
| return buffer; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| const char *AVCProfileToString(uint8_t profile) { |
| switch (profile) { |
| case kAVCProfileBaseline: |
| return "Baseline"; |
| case kAVCProfileMain: |
| return "Main"; |
| case kAVCProfileExtended: |
| return "Extended"; |
| case kAVCProfileHigh: |
| return "High"; |
| case kAVCProfileHigh10: |
| return "High 10"; |
| case kAVCProfileHigh422: |
| return "High 422"; |
| case kAVCProfileHigh444: |
| return "High 444"; |
| case kAVCProfileCAVLC444Intra: |
| return "CAVLC 444 Intra"; |
| default: return "Unknown"; |
| } |
| } |
| |
| sp<MetaData> MakeAVCCodecSpecificData(const sp<ABuffer> &accessUnit) { |
| const uint8_t *data = accessUnit->data(); |
| size_t size = accessUnit->size(); |
| |
| sp<ABuffer> seqParamSet = FindNAL(data, size, 7); |
| if (seqParamSet == NULL) { |
| return NULL; |
| } |
| |
| int32_t width, height; |
| int32_t sarWidth, sarHeight; |
| FindAVCDimensions( |
| seqParamSet, &width, &height, &sarWidth, &sarHeight); |
| |
| sp<ABuffer> picParamSet = FindNAL(data, size, 8); |
| CHECK(picParamSet != NULL); |
| |
| size_t csdSize = |
| 1 + 3 + 1 + 1 |
| + 2 * 1 + seqParamSet->size() |
| + 1 + 2 * 1 + picParamSet->size(); |
| |
| sp<ABuffer> csd = new ABuffer(csdSize); |
| uint8_t *out = csd->data(); |
| |
| *out++ = 0x01; // configurationVersion |
| memcpy(out, seqParamSet->data() + 1, 3); // profile/level... |
| |
| uint8_t profile = out[0]; |
| uint8_t level = out[2]; |
| |
| out += 3; |
| *out++ = (0x3f << 2) | 1; // lengthSize == 2 bytes |
| *out++ = 0xe0 | 1; |
| |
| *out++ = seqParamSet->size() >> 8; |
| *out++ = seqParamSet->size() & 0xff; |
| memcpy(out, seqParamSet->data(), seqParamSet->size()); |
| out += seqParamSet->size(); |
| |
| *out++ = 1; |
| |
| *out++ = picParamSet->size() >> 8; |
| *out++ = picParamSet->size() & 0xff; |
| memcpy(out, picParamSet->data(), picParamSet->size()); |
| |
| #if 0 |
| ALOGI("AVC seq param set"); |
| hexdump(seqParamSet->data(), seqParamSet->size()); |
| #endif |
| |
| sp<MetaData> meta = new MetaData; |
| meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_AVC); |
| |
| meta->setData(kKeyAVCC, kTypeAVCC, csd->data(), csd->size()); |
| meta->setInt32(kKeyWidth, width); |
| meta->setInt32(kKeyHeight, height); |
| |
| if ((sarWidth > 0 && sarHeight > 0) && (sarWidth != 1 || sarHeight != 1)) { |
| // We treat *:0 and 0:* (unspecified) as 1:1. |
| |
| meta->setInt32(kKeySARWidth, sarWidth); |
| meta->setInt32(kKeySARHeight, sarHeight); |
| |
| ALOGI("found AVC codec config (%d x %d, %s-profile level %d.%d) " |
| "SAR %d : %d", |
| width, |
| height, |
| AVCProfileToString(profile), |
| level / 10, |
| level % 10, |
| sarWidth, |
| sarHeight); |
| } else { |
| ALOGI("found AVC codec config (%d x %d, %s-profile level %d.%d)", |
| width, |
| height, |
| AVCProfileToString(profile), |
| level / 10, |
| level % 10); |
| } |
| |
| return meta; |
| } |
| |
| template <typename T> |
| bool IsIDRInternal(const sp<T> &buffer) { |
| const uint8_t *data = buffer->data(); |
| size_t size = buffer->size(); |
| |
| bool foundIDR = false; |
| |
| const uint8_t *nalStart; |
| size_t nalSize; |
| while (getNextNALUnit(&data, &size, &nalStart, &nalSize, true) == OK) { |
| if (nalSize == 0u) { |
| ALOGW("skipping empty nal unit from potentially malformed bitstream"); |
| continue; |
| } |
| |
| unsigned nalType = nalStart[0] & 0x1f; |
| |
| if (nalType == 5) { |
| foundIDR = true; |
| break; |
| } |
| } |
| |
| return foundIDR; |
| } |
| |
| bool IsIDR(const sp<ABuffer> &buffer) { |
| return IsIDRInternal(buffer); |
| } |
| |
| bool IsIDR(const sp<MediaCodecBuffer> &buffer) { |
| return IsIDRInternal(buffer); |
| } |
| |
| bool IsAVCReferenceFrame(const sp<ABuffer> &accessUnit) { |
| const uint8_t *data = accessUnit->data(); |
| size_t size = accessUnit->size(); |
| if (data == NULL) { |
| ALOGE("IsAVCReferenceFrame: called on NULL data (%p, %zu)", accessUnit.get(), size); |
| return false; |
| } |
| |
| const uint8_t *nalStart; |
| size_t nalSize; |
| while (getNextNALUnit(&data, &size, &nalStart, &nalSize, true) == OK) { |
| if (nalSize == 0) { |
| ALOGE("IsAVCReferenceFrame: invalid nalSize: 0 (%p, %zu)", accessUnit.get(), size); |
| return false; |
| } |
| |
| unsigned nalType = nalStart[0] & 0x1f; |
| |
| if (nalType == 5) { |
| return true; |
| } else if (nalType == 1) { |
| unsigned nal_ref_idc = (nalStart[0] >> 5) & 3; |
| return nal_ref_idc != 0; |
| } |
| } |
| |
| return true; |
| } |
| |
| uint32_t FindAVCLayerId(const uint8_t *data, size_t size) { |
| CHECK(data != NULL); |
| |
| const unsigned kSvcNalType = 0xE; |
| const unsigned kSvcNalSearchRange = 32; |
| // SVC NAL |
| // |---0 1110|1--- ----|---- ----|iii- ---| |
| // ^ ^ |
| // NAL-type = 0xE layer-Id |
| // |
| // layer_id 0 is for base layer, while 1, 2, ... are enhancement layers. |
| // Layer n uses reference frames from layer 0, 1, ..., n-1. |
| |
| uint32_t layerId = 0; |
| sp<ABuffer> svcNAL = FindNAL( |
| data, size > kSvcNalSearchRange ? kSvcNalSearchRange : size, kSvcNalType); |
| if (svcNAL != NULL && svcNAL->size() >= 4) { |
| layerId = (*(svcNAL->data() + 3) >> 5) & 0x7; |
| } |
| return layerId; |
| } |
| |
| sp<MetaData> MakeAACCodecSpecificData( |
| unsigned profile, unsigned sampling_freq_index, |
| unsigned channel_configuration) { |
| sp<MetaData> meta = new MetaData; |
| meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_AAC); |
| |
| CHECK_LE(sampling_freq_index, 11u); |
| static const int32_t kSamplingFreq[] = { |
| 96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, |
| 16000, 12000, 11025, 8000 |
| }; |
| meta->setInt32(kKeySampleRate, kSamplingFreq[sampling_freq_index]); |
| meta->setInt32(kKeyChannelCount, channel_configuration); |
| |
| static const uint8_t kStaticESDS[] = { |
| 0x03, 22, |
| 0x00, 0x00, // ES_ID |
| 0x00, // streamDependenceFlag, URL_Flag, OCRstreamFlag |
| |
| 0x04, 17, |
| 0x40, // Audio ISO/IEC 14496-3 |
| 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, |
| |
| 0x05, 2, |
| // AudioSpecificInfo follows |
| |
| // oooo offf fccc c000 |
| // o - audioObjectType |
| // f - samplingFreqIndex |
| // c - channelConfig |
| }; |
| sp<ABuffer> csd = new ABuffer(sizeof(kStaticESDS) + 2); |
| memcpy(csd->data(), kStaticESDS, sizeof(kStaticESDS)); |
| |
| csd->data()[sizeof(kStaticESDS)] = |
| ((profile + 1) << 3) | (sampling_freq_index >> 1); |
| |
| csd->data()[sizeof(kStaticESDS) + 1] = |
| ((sampling_freq_index << 7) & 0x80) | (channel_configuration << 3); |
| |
| meta->setData(kKeyESDS, 0, csd->data(), csd->size()); |
| |
| return meta; |
| } |
| |
| bool ExtractDimensionsFromVOLHeader( |
| const uint8_t *data, size_t size, int32_t *width, int32_t *height) { |
| ABitReader br(&data[4], size - 4); |
| br.skipBits(1); // random_accessible_vol |
| unsigned video_object_type_indication = br.getBits(8); |
| |
| CHECK_NE(video_object_type_indication, |
| 0x21u /* Fine Granularity Scalable */); |
| |
| unsigned video_object_layer_verid __unused; |
| unsigned video_object_layer_priority __unused; |
| if (br.getBits(1)) { |
| video_object_layer_verid = br.getBits(4); |
| video_object_layer_priority = br.getBits(3); |
| } |
| unsigned aspect_ratio_info = br.getBits(4); |
| if (aspect_ratio_info == 0x0f /* extended PAR */) { |
| br.skipBits(8); // par_width |
| br.skipBits(8); // par_height |
| } |
| if (br.getBits(1)) { // vol_control_parameters |
| br.skipBits(2); // chroma_format |
| br.skipBits(1); // low_delay |
| if (br.getBits(1)) { // vbv_parameters |
| br.skipBits(15); // first_half_bit_rate |
| CHECK(br.getBits(1)); // marker_bit |
| br.skipBits(15); // latter_half_bit_rate |
| CHECK(br.getBits(1)); // marker_bit |
| br.skipBits(15); // first_half_vbv_buffer_size |
| CHECK(br.getBits(1)); // marker_bit |
| br.skipBits(3); // latter_half_vbv_buffer_size |
| br.skipBits(11); // first_half_vbv_occupancy |
| CHECK(br.getBits(1)); // marker_bit |
| br.skipBits(15); // latter_half_vbv_occupancy |
| CHECK(br.getBits(1)); // marker_bit |
| } |
| } |
| unsigned video_object_layer_shape = br.getBits(2); |
| CHECK_EQ(video_object_layer_shape, 0x00u /* rectangular */); |
| |
| CHECK(br.getBits(1)); // marker_bit |
| unsigned vop_time_increment_resolution = br.getBits(16); |
| CHECK(br.getBits(1)); // marker_bit |
| |
| if (br.getBits(1)) { // fixed_vop_rate |
| // range [0..vop_time_increment_resolution) |
| |
| // vop_time_increment_resolution |
| // 2 => 0..1, 1 bit |
| // 3 => 0..2, 2 bits |
| // 4 => 0..3, 2 bits |
| // 5 => 0..4, 3 bits |
| // ... |
| |
| CHECK_GT(vop_time_increment_resolution, 0u); |
| --vop_time_increment_resolution; |
| |
| unsigned numBits = 0; |
| while (vop_time_increment_resolution > 0) { |
| ++numBits; |
| vop_time_increment_resolution >>= 1; |
| } |
| |
| br.skipBits(numBits); // fixed_vop_time_increment |
| } |
| |
| CHECK(br.getBits(1)); // marker_bit |
| unsigned video_object_layer_width = br.getBits(13); |
| CHECK(br.getBits(1)); // marker_bit |
| unsigned video_object_layer_height = br.getBits(13); |
| CHECK(br.getBits(1)); // marker_bit |
| |
| unsigned interlaced __unused = br.getBits(1); |
| |
| *width = video_object_layer_width; |
| *height = video_object_layer_height; |
| |
| return true; |
| } |
| |
| bool GetMPEGAudioFrameSize( |
| uint32_t header, size_t *frame_size, |
| int *out_sampling_rate, int *out_channels, |
| int *out_bitrate, int *out_num_samples) { |
| *frame_size = 0; |
| |
| if (out_sampling_rate) { |
| *out_sampling_rate = 0; |
| } |
| |
| if (out_channels) { |
| *out_channels = 0; |
| } |
| |
| if (out_bitrate) { |
| *out_bitrate = 0; |
| } |
| |
| if (out_num_samples) { |
| *out_num_samples = 1152; |
| } |
| |
| if ((header & 0xffe00000) != 0xffe00000) { |
| return false; |
| } |
| |
| unsigned version = (header >> 19) & 3; |
| |
| if (version == 0x01) { |
| return false; |
| } |
| |
| unsigned layer = (header >> 17) & 3; |
| |
| if (layer == 0x00) { |
| return false; |
| } |
| |
| unsigned protection __unused = (header >> 16) & 1; |
| |
| unsigned bitrate_index = (header >> 12) & 0x0f; |
| |
| if (bitrate_index == 0 || bitrate_index == 0x0f) { |
| // Disallow "free" bitrate. |
| return false; |
| } |
| |
| unsigned sampling_rate_index = (header >> 10) & 3; |
| |
| if (sampling_rate_index == 3) { |
| return false; |
| } |
| |
| static const int kSamplingRateV1[] = { 44100, 48000, 32000 }; |
| int sampling_rate = kSamplingRateV1[sampling_rate_index]; |
| if (version == 2 /* V2 */) { |
| sampling_rate /= 2; |
| } else if (version == 0 /* V2.5 */) { |
| sampling_rate /= 4; |
| } |
| |
| unsigned padding = (header >> 9) & 1; |
| |
| if (layer == 3) { |
| // layer I |
| |
| static const int kBitrateV1[] = { |
| 32, 64, 96, 128, 160, 192, 224, 256, |
| 288, 320, 352, 384, 416, 448 |
| }; |
| |
| static const int kBitrateV2[] = { |
| 32, 48, 56, 64, 80, 96, 112, 128, |
| 144, 160, 176, 192, 224, 256 |
| }; |
| |
| int bitrate = |
| (version == 3 /* V1 */) |
| ? kBitrateV1[bitrate_index - 1] |
| : kBitrateV2[bitrate_index - 1]; |
| |
| if (out_bitrate) { |
| *out_bitrate = bitrate; |
| } |
| |
| *frame_size = (12000 * bitrate / sampling_rate + padding) * 4; |
| |
| if (out_num_samples) { |
| *out_num_samples = 384; |
| } |
| } else { |
| // layer II or III |
| |
| static const int kBitrateV1L2[] = { |
| 32, 48, 56, 64, 80, 96, 112, 128, |
| 160, 192, 224, 256, 320, 384 |
| }; |
| |
| static const int kBitrateV1L3[] = { |
| 32, 40, 48, 56, 64, 80, 96, 112, |
| 128, 160, 192, 224, 256, 320 |
| }; |
| |
| static const int kBitrateV2[] = { |
| 8, 16, 24, 32, 40, 48, 56, 64, |
| 80, 96, 112, 128, 144, 160 |
| }; |
| |
| int bitrate; |
| if (version == 3 /* V1 */) { |
| bitrate = (layer == 2 /* L2 */) |
| ? kBitrateV1L2[bitrate_index - 1] |
| : kBitrateV1L3[bitrate_index - 1]; |
| |
| if (out_num_samples) { |
| *out_num_samples = 1152; |
| } |
| } else { |
| // V2 (or 2.5) |
| |
| bitrate = kBitrateV2[bitrate_index - 1]; |
| if (out_num_samples) { |
| *out_num_samples = (layer == 1 /* L3 */) ? 576 : 1152; |
| } |
| } |
| |
| if (out_bitrate) { |
| *out_bitrate = bitrate; |
| } |
| |
| if (version == 3 /* V1 */) { |
| *frame_size = 144000 * bitrate / sampling_rate + padding; |
| } else { |
| // V2 or V2.5 |
| size_t tmp = (layer == 1 /* L3 */) ? 72000 : 144000; |
| *frame_size = tmp * bitrate / sampling_rate + padding; |
| } |
| } |
| |
| if (out_sampling_rate) { |
| *out_sampling_rate = sampling_rate; |
| } |
| |
| if (out_channels) { |
| int channel_mode = (header >> 6) & 3; |
| |
| *out_channels = (channel_mode == 3) ? 1 : 2; |
| } |
| |
| return true; |
| } |
| |
| } // namespace android |
| |