| /********** |
| This library is free software; you can redistribute it and/or modify it under |
| the terms of the GNU Lesser General Public License as published by the |
| Free Software Foundation; either version 3 of the License, or (at your |
| option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.) |
| |
| This library is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for |
| more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this library; if not, write to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| **********/ |
| // "liveMedia" |
| // Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved. |
| // A source object for AMR audio files (as defined in RFC 4867, section 5) |
| // Implementation |
| |
| #include "AMRAudioFileSource.hh" |
| #include "InputFile.hh" |
| #include "GroupsockHelper.hh" |
| |
| ////////// AMRAudioFileSource ////////// |
| |
| AMRAudioFileSource* |
| AMRAudioFileSource::createNew(UsageEnvironment& env, char const* fileName) { |
| FILE* fid = NULL; |
| Boolean magicNumberOK = True; |
| do { |
| |
| fid = OpenInputFile(env, fileName); |
| if (fid == NULL) break; |
| |
| // Now, having opened the input file, read the first few bytes, to |
| // check the required 'magic number': |
| magicNumberOK = False; // until we learn otherwise |
| Boolean isWideband = False; // by default |
| unsigned numChannels = 1; // by default |
| char buf[100]; |
| // Start with the first 6 bytes (the first 5 of which must be "#!AMR"): |
| if (fread(buf, 1, 6, fid) < 6) break; |
| if (strncmp(buf, "#!AMR", 5) != 0) break; // bad magic # |
| unsigned bytesRead = 6; |
| |
| // The next bytes must be "\n", "-WB\n", "_MC1.0\n", or "-WB_MC1.0\n" |
| if (buf[5] == '-') { |
| // The next bytes must be "WB\n" or "WB_MC1.0\n" |
| if (fread(&buf[bytesRead], 1, 3, fid) < 3) break; |
| if (strncmp(&buf[bytesRead], "WB", 2) != 0) break; // bad magic # |
| isWideband = True; |
| bytesRead += 3; |
| } |
| if (buf[bytesRead-1] == '_') { |
| // The next bytes must be "MC1.0\n" |
| if (fread(&buf[bytesRead], 1, 6, fid) < 6) break; |
| if (strncmp(&buf[bytesRead], "MC1.0\n", 6) != 0) break; // bad magic # |
| bytesRead += 6; |
| |
| // The next 4 bytes contain the number of channels: |
| char channelDesc[4]; |
| if (fread(channelDesc, 1, 4, fid) < 4) break; |
| numChannels = channelDesc[3]&0xF; |
| } else if (buf[bytesRead-1] != '\n') { |
| break; // bad magic # |
| } |
| |
| // If we get here, the magic number was OK: |
| magicNumberOK = True; |
| |
| #ifdef DEBUG |
| fprintf(stderr, "isWideband: %d, numChannels: %d\n", |
| isWideband, numChannels); |
| #endif |
| return new AMRAudioFileSource(env, fid, isWideband, numChannels); |
| } while (0); |
| |
| // An error occurred: |
| CloseInputFile(fid); |
| if (!magicNumberOK) { |
| env.setResultMsg("Bad (or nonexistent) AMR file header"); |
| } |
| return NULL; |
| } |
| |
| AMRAudioFileSource |
| ::AMRAudioFileSource(UsageEnvironment& env, FILE* fid, |
| Boolean isWideband, unsigned numChannels) |
| : AMRAudioSource(env, isWideband, numChannels), |
| fFid(fid) { |
| } |
| |
| AMRAudioFileSource::~AMRAudioFileSource() { |
| CloseInputFile(fFid); |
| } |
| |
| // The mapping from the "FT" field to frame size. |
| // Values of 65535 are invalid. |
| #define FT_INVALID 65535 |
| static unsigned short const frameSize[16] = { |
| 12, 13, 15, 17, |
| 19, 20, 26, 31, |
| 5, FT_INVALID, FT_INVALID, FT_INVALID, |
| FT_INVALID, FT_INVALID, FT_INVALID, 0 |
| }; |
| static unsigned short const frameSizeWideband[16] = { |
| 17, 23, 32, 36, |
| 40, 46, 50, 58, |
| 60, 5, FT_INVALID, FT_INVALID, |
| FT_INVALID, FT_INVALID, 0, 0 |
| }; |
| |
| // Note: We should change the following to use asynchronous file reading, ##### |
| // as we now do with ByteStreamFileSource. ##### |
| void AMRAudioFileSource::doGetNextFrame() { |
| if (feof(fFid) || ferror(fFid)) { |
| handleClosure(); |
| return; |
| } |
| |
| // Begin by reading the 1-byte frame header (and checking it for validity) |
| while (1) { |
| if (fread(&fLastFrameHeader, 1, 1, fFid) < 1) { |
| handleClosure(); |
| return; |
| } |
| if ((fLastFrameHeader&0x83) != 0) { |
| #ifdef DEBUG |
| fprintf(stderr, "Invalid frame header 0x%02x (padding bits (0x83) are not zero)\n", fLastFrameHeader); |
| #endif |
| } else { |
| unsigned char ft = (fLastFrameHeader&0x78)>>3; |
| fFrameSize = fIsWideband ? frameSizeWideband[ft] : frameSize[ft]; |
| if (fFrameSize == FT_INVALID) { |
| #ifdef DEBUG |
| fprintf(stderr, "Invalid FT field %d (from frame header 0x%02x)\n", |
| ft, fLastFrameHeader); |
| #endif |
| } else { |
| // The frame header is OK |
| #ifdef DEBUG |
| fprintf(stderr, "Valid frame header 0x%02x -> ft %d -> frame size %d\n", fLastFrameHeader, ft, fFrameSize); |
| #endif |
| break; |
| } |
| } |
| } |
| |
| // Next, read the frame-block into the buffer provided: |
| fFrameSize *= fNumChannels; // because multiple channels make up a frame-block |
| if (fFrameSize > fMaxSize) { |
| fNumTruncatedBytes = fFrameSize - fMaxSize; |
| fFrameSize = fMaxSize; |
| } |
| fFrameSize = fread(fTo, 1, fFrameSize, fFid); |
| |
| // Set the 'presentation time': |
| if (fPresentationTime.tv_sec == 0 && fPresentationTime.tv_usec == 0) { |
| // This is the first frame, so use the current time: |
| gettimeofday(&fPresentationTime, NULL); |
| } else { |
| // Increment by the play time of the previous frame (20 ms) |
| unsigned uSeconds = fPresentationTime.tv_usec + 20000; |
| fPresentationTime.tv_sec += uSeconds/1000000; |
| fPresentationTime.tv_usec = uSeconds%1000000; |
| } |
| |
| fDurationInMicroseconds = 20000; // each frame is 20 ms |
| |
| // Switch to another task, and inform the reader that he has data: |
| nextTask() = envir().taskScheduler().scheduleDelayedTask(0, |
| (TaskFunc*)FramedSource::afterGetting, this); |
| } |