| /* |
| * Copyrightm (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. |
| */ |
| |
| #include <string.h> |
| |
| #include "AudioCodec.h" |
| |
| #include "gsmamr_dec.h" |
| #include "gsmamr_enc.h" |
| |
| namespace { |
| |
| const int gFrameBits[8] = {95, 103, 118, 134, 148, 159, 204, 244}; |
| |
| //------------------------------------------------------------------------------ |
| |
| // See RFC 4867 for the encoding details. |
| |
| class AmrCodec : public AudioCodec |
| { |
| public: |
| AmrCodec() { |
| if (AMREncodeInit(&mEncoder, &mSidSync, false)) { |
| mEncoder = NULL; |
| } |
| if (GSMInitDecode(&mDecoder, (Word8 *)"RTP")) { |
| mDecoder = NULL; |
| } |
| } |
| |
| ~AmrCodec() { |
| if (mEncoder) { |
| AMREncodeExit(&mEncoder, &mSidSync); |
| } |
| if (mDecoder) { |
| GSMDecodeFrameExit(&mDecoder); |
| } |
| } |
| |
| int set(int sampleRate, const char *fmtp); |
| int encode(void *payload, int16_t *samples); |
| int decode(int16_t *samples, void *payload, int length); |
| |
| private: |
| void *mEncoder; |
| void *mSidSync; |
| void *mDecoder; |
| |
| int mMode; |
| int mModeSet; |
| bool mOctetAligned; |
| }; |
| |
| int AmrCodec::set(int sampleRate, const char *fmtp) |
| { |
| // These parameters are not supported. |
| if (strcasestr(fmtp, "crc=1") || strcasestr(fmtp, "robust-sorting=1") || |
| strcasestr(fmtp, "interleaving=")) { |
| return -1; |
| } |
| |
| // Handle mode-set and octet-align. |
| const char *modes = strcasestr(fmtp, "mode-set="); |
| if (modes) { |
| mMode = 0; |
| mModeSet = 0; |
| for (char c = *modes; c && c != ' '; c = *++modes) { |
| if (c >= '0' && c <= '7') { |
| int mode = c - '0'; |
| if (mode > mMode) { |
| mMode = mode; |
| } |
| mModeSet |= 1 << mode; |
| } |
| } |
| } else { |
| mMode = 7; |
| mModeSet = 0xFF; |
| } |
| mOctetAligned = (strcasestr(fmtp, "octet-align=1") != NULL); |
| |
| // TODO: handle mode-change-*. |
| |
| return (sampleRate == 8000 && mEncoder && mDecoder) ? 160 : -1; |
| } |
| |
| int AmrCodec::encode(void *payload, int16_t *samples) |
| { |
| unsigned char *bytes = (unsigned char *)payload; |
| Frame_Type_3GPP type; |
| |
| int length = AMREncode(mEncoder, mSidSync, (Mode)mMode, |
| samples, bytes + 1, &type, AMR_TX_WMF); |
| |
| if (type != mMode || length != (8 + gFrameBits[mMode] + 7) >> 3) { |
| return -1; |
| } |
| |
| if (mOctetAligned) { |
| bytes[0] = 0xF0; |
| bytes[1] = (mMode << 3) | 0x04; |
| ++length; |
| } else { |
| // CMR = 15 (4-bit), F = 0 (1-bit), FT = mMode (4-bit), Q = 1 (1-bit). |
| bytes[0] = 0xFF; |
| bytes[1] = 0xC0 | (mMode << 1) | 1; |
| |
| // Shift left 6 bits and update the length. |
| bytes[length + 1] = 0; |
| for (int i = 0; i <= length; ++i) { |
| bytes[i] = (bytes[i] << 6) | (bytes[i + 1] >> 2); |
| } |
| length = (10 + gFrameBits[mMode] + 7) >> 3; |
| } |
| return length; |
| } |
| |
| int AmrCodec::decode(int16_t *samples, void *payload, int length) |
| { |
| unsigned char *bytes = (unsigned char *)payload; |
| Frame_Type_3GPP type; |
| if (length < 2) { |
| return -1; |
| } |
| int request = bytes[0] >> 4; |
| |
| if (mOctetAligned) { |
| if ((bytes[1] & 0xC4) != 0x04) { |
| return -1; |
| } |
| type = (Frame_Type_3GPP)(bytes[1] >> 3); |
| if (length != (16 + gFrameBits[type] + 7) >> 3) { |
| return -1; |
| } |
| length -= 2; |
| bytes += 2; |
| } else { |
| if ((bytes[0] & 0x0C) || !(bytes[1] & 0x40)) { |
| return -1; |
| } |
| type = (Frame_Type_3GPP)((bytes[0] << 1 | bytes[1] >> 7) & 0x07); |
| if (length != (10 + gFrameBits[type] + 7) >> 3) { |
| return -1; |
| } |
| |
| // Shift left 2 bits and update the length. |
| --length; |
| for (int i = 1; i < length; ++i) { |
| bytes[i] = (bytes[i] << 2) | (bytes[i + 1] >> 6); |
| } |
| bytes[length] <<= 2; |
| length = (gFrameBits[type] + 7) >> 3; |
| ++bytes; |
| } |
| |
| if (AMRDecode(mDecoder, type, bytes, samples, MIME_IETF) != length) { |
| return -1; |
| } |
| |
| // Handle CMR |
| if (request < 8 && request != mMode) { |
| for (int i = request; i >= 0; --i) { |
| if (mModeSet & (1 << i)) { |
| mMode = request; |
| break; |
| } |
| } |
| } |
| |
| return 160; |
| } |
| |
| //------------------------------------------------------------------------------ |
| |
| // See RFC 3551 for the encoding details. |
| |
| class GsmEfrCodec : public AudioCodec |
| { |
| public: |
| GsmEfrCodec() { |
| if (AMREncodeInit(&mEncoder, &mSidSync, false)) { |
| mEncoder = NULL; |
| } |
| if (GSMInitDecode(&mDecoder, (Word8 *)"RTP")) { |
| mDecoder = NULL; |
| } |
| } |
| |
| ~GsmEfrCodec() { |
| if (mEncoder) { |
| AMREncodeExit(&mEncoder, &mSidSync); |
| } |
| if (mDecoder) { |
| GSMDecodeFrameExit(&mDecoder); |
| } |
| } |
| |
| int set(int sampleRate, const char *fmtp) { |
| return (sampleRate == 8000 && mEncoder && mDecoder) ? 160 : -1; |
| } |
| |
| int encode(void *payload, int16_t *samples); |
| int decode(int16_t *samples, void *payload, int length); |
| |
| private: |
| void *mEncoder; |
| void *mSidSync; |
| void *mDecoder; |
| }; |
| |
| int GsmEfrCodec::encode(void *payload, int16_t *samples) |
| { |
| unsigned char *bytes = (unsigned char *)payload; |
| Frame_Type_3GPP type; |
| |
| int length = AMREncode(mEncoder, mSidSync, MR122, |
| samples, bytes, &type, AMR_TX_WMF); |
| |
| if (type == AMR_122 && length == 32) { |
| bytes[0] = 0xC0 | (bytes[1] >> 4); |
| for (int i = 1; i < 31; ++i) { |
| bytes[i] = (bytes[i] << 4) | (bytes[i + 1] >> 4); |
| } |
| return 31; |
| } |
| return -1; |
| } |
| |
| int GsmEfrCodec::decode(int16_t *samples, void *payload, int length) |
| { |
| unsigned char *bytes = (unsigned char *)payload; |
| if (length == 31 && (bytes[0] >> 4) == 0x0C) { |
| for (int i = 0; i < 30; ++i) { |
| bytes[i] = (bytes[i] << 4) | (bytes[i + 1] >> 4); |
| } |
| bytes[30] <<= 4; |
| |
| if (AMRDecode(mDecoder, AMR_122, bytes, samples, MIME_IETF) == 31) { |
| return 160; |
| } |
| } |
| return -1; |
| } |
| |
| } // namespace |
| |
| AudioCodec *newAmrCodec() |
| { |
| return new AmrCodec; |
| } |
| |
| AudioCodec *newGsmEfrCodec() |
| { |
| return new GsmEfrCodec; |
| } |