354 lines
12 KiB
C++
354 lines
12 KiB
C++
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/**********
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This library is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
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This library is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
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more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this library; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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**********/
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// "liveMedia"
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// Copyright (c) 1996-2016 Live Networks, Inc. All rights reserved.
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// A WAV audio file source
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// Implementation
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#include "WAVAudioFileSource.hh"
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#include "InputFile.hh"
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#include "GroupsockHelper.hh"
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////////// WAVAudioFileSource //////////
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WAVAudioFileSource*
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WAVAudioFileSource::createNew(UsageEnvironment& env, char const* fileName) {
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do {
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FILE* fid = OpenInputFile(env, fileName);
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if (fid == NULL) break;
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WAVAudioFileSource* newSource = new WAVAudioFileSource(env, fid);
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if (newSource != NULL && newSource->bitsPerSample() == 0) {
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// The WAV file header was apparently invalid.
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Medium::close(newSource);
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break;
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}
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newSource->fFileSize = (unsigned)GetFileSize(fileName, fid);
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return newSource;
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} while (0);
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return NULL;
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}
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unsigned WAVAudioFileSource::numPCMBytes() const {
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if (fFileSize < fWAVHeaderSize) return 0;
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return fFileSize - fWAVHeaderSize;
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}
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void WAVAudioFileSource::setScaleFactor(int scale) {
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if (!fFidIsSeekable) return; // we can't do 'trick play' operations on non-seekable files
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fScaleFactor = scale;
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if (fScaleFactor < 0 && TellFile64(fFid) > 0) {
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// Because we're reading backwards, seek back one sample, to ensure that
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// (i) we start reading the last sample before the start point, and
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// (ii) we don't hit end-of-file on the first read.
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int bytesPerSample = (fNumChannels*fBitsPerSample)/8;
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if (bytesPerSample == 0) bytesPerSample = 1;
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SeekFile64(fFid, -bytesPerSample, SEEK_CUR);
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}
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}
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void WAVAudioFileSource::seekToPCMByte(unsigned byteNumber) {
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byteNumber += fWAVHeaderSize;
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if (byteNumber > fFileSize) byteNumber = fFileSize;
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SeekFile64(fFid, byteNumber, SEEK_SET);
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}
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void WAVAudioFileSource::limitNumBytesToStream(unsigned numBytesToStream) {
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fNumBytesToStream = numBytesToStream;
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fLimitNumBytesToStream = fNumBytesToStream > 0;
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}
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unsigned char WAVAudioFileSource::getAudioFormat() {
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return fAudioFormat;
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}
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#define nextc fgetc(fid)
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static Boolean get4Bytes(FILE* fid, u_int32_t& result) { // little-endian
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int c0, c1, c2, c3;
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if ((c0 = nextc) == EOF || (c1 = nextc) == EOF ||
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(c2 = nextc) == EOF || (c3 = nextc) == EOF) return False;
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result = (c3<<24)|(c2<<16)|(c1<<8)|c0;
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return True;
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}
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static Boolean get2Bytes(FILE* fid, u_int16_t& result) {//little-endian
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int c0, c1;
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if ((c0 = nextc) == EOF || (c1 = nextc) == EOF) return False;
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result = (c1<<8)|c0;
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return True;
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}
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static Boolean skipBytes(FILE* fid, int num) {
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while (num-- > 0) {
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if (nextc == EOF) return False;
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}
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return True;
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}
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WAVAudioFileSource::WAVAudioFileSource(UsageEnvironment& env, FILE* fid)
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: AudioInputDevice(env, 0, 0, 0, 0)/* set the real parameters later */,
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fFid(fid), fFidIsSeekable(False), fLastPlayTime(0), fHaveStartedReading(False), fWAVHeaderSize(0), fFileSize(0),
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fScaleFactor(1), fLimitNumBytesToStream(False), fNumBytesToStream(0), fAudioFormat(WA_UNKNOWN) {
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// Check the WAV file header for validity.
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// Note: The following web pages contain info about the WAV format:
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// http://www.ringthis.com/dev/wave_format.htm
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// http://www.lightlink.com/tjweber/StripWav/Canon.html
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// http://www.onicos.com/staff/iz/formats/wav.html
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Boolean success = False; // until we learn otherwise
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do {
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// RIFF Chunk:
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if (nextc != 'R' || nextc != 'I' || nextc != 'F' || nextc != 'F') break;
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if (!skipBytes(fid, 4)) break;
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if (nextc != 'W' || nextc != 'A' || nextc != 'V' || nextc != 'E') break;
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// Skip over any chunk that's not a FORMAT ('fmt ') chunk:
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u_int32_t tmp;
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if (!get4Bytes(fid, tmp)) break;
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while (tmp != 0x20746d66/*'fmt ', little-endian*/) {
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// Skip this chunk:
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u_int32_t chunkLength;
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if (!get4Bytes(fid, chunkLength)) break;
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if (!skipBytes(fid, chunkLength)) break;
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if (!get4Bytes(fid, tmp)) break;
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}
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// FORMAT Chunk (the 4-byte header code has already been parsed):
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unsigned formatLength;
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if (!get4Bytes(fid, formatLength)) break;
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unsigned short audioFormat;
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if (!get2Bytes(fid, audioFormat)) break;
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fAudioFormat = (unsigned char)audioFormat;
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if (fAudioFormat != WA_PCM && fAudioFormat != WA_PCMA && fAudioFormat != WA_PCMU && fAudioFormat != WA_IMA_ADPCM) {
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// It's a format that we don't (yet) understand
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env.setResultMsg("Audio format is not one that we handle (PCM/PCMU/PCMA or IMA ADPCM)");
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break;
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}
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unsigned short numChannels;
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if (!get2Bytes(fid, numChannels)) break;
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fNumChannels = (unsigned char)numChannels;
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if (fNumChannels < 1 || fNumChannels > 2) { // invalid # channels
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char errMsg[100];
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sprintf(errMsg, "Bad # channels: %d", fNumChannels);
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env.setResultMsg(errMsg);
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break;
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}
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if (!get4Bytes(fid, fSamplingFrequency)) break;
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if (fSamplingFrequency == 0) {
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env.setResultMsg("Bad sampling frequency: 0");
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break;
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}
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if (!skipBytes(fid, 6)) break; // "nAvgBytesPerSec" (4 bytes) + "nBlockAlign" (2 bytes)
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unsigned short bitsPerSample;
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if (!get2Bytes(fid, bitsPerSample)) break;
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fBitsPerSample = (unsigned char)bitsPerSample;
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if (fBitsPerSample == 0) {
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env.setResultMsg("Bad bits-per-sample: 0");
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break;
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}
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if (!skipBytes(fid, formatLength - 16)) break;
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// FACT chunk (optional):
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int c = nextc;
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if (c == 'f') {
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if (nextc != 'a' || nextc != 'c' || nextc != 't') break;
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unsigned factLength;
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if (!get4Bytes(fid, factLength)) break;
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if (!skipBytes(fid, factLength)) break;
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c = nextc;
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}
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// EYRE chunk (optional):
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if (c == 'e') {
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if (nextc != 'y' || nextc != 'r' || nextc != 'e') break;
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unsigned eyreLength;
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if (!get4Bytes(fid, eyreLength)) break;
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if (!skipBytes(fid, eyreLength)) break;
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c = nextc;
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}
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// DATA Chunk:
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if (c != 'd' || nextc != 'a' || nextc != 't' || nextc != 'a') break;
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if (!skipBytes(fid, 4)) break;
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// The header is good; the remaining data are the sample bytes.
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fWAVHeaderSize = (unsigned)TellFile64(fid);
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success = True;
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} while (0);
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if (!success) {
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env.setResultMsg("Bad WAV file format");
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// Set "fBitsPerSample" to zero, to indicate failure:
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fBitsPerSample = 0;
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return;
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}
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fPlayTimePerSample = 1e6/(double)fSamplingFrequency;
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// Although PCM is a sample-based format, we group samples into
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// 'frames' for efficient delivery to clients. Set up our preferred
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// frame size to be close to 20 ms, if possible, but always no greater
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// than 1400 bytes (to ensure that it will fit in a single RTP packet)
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unsigned maxSamplesPerFrame = (1400*8)/(fNumChannels*fBitsPerSample);
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unsigned desiredSamplesPerFrame = (unsigned)(0.02*fSamplingFrequency);
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unsigned samplesPerFrame = desiredSamplesPerFrame < maxSamplesPerFrame ? desiredSamplesPerFrame : maxSamplesPerFrame;
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fPreferredFrameSize = (samplesPerFrame*fNumChannels*fBitsPerSample)/8;
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fFidIsSeekable = FileIsSeekable(fFid);
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#ifndef READ_FROM_FILES_SYNCHRONOUSLY
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// Now that we've finished reading the WAV header, all future reads (of audio samples) from the file will be asynchronous:
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makeSocketNonBlocking(fileno(fFid));
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#endif
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}
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WAVAudioFileSource::~WAVAudioFileSource() {
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if (fFid == NULL) return;
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#ifndef READ_FROM_FILES_SYNCHRONOUSLY
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envir().taskScheduler().turnOffBackgroundReadHandling(fileno(fFid));
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#endif
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CloseInputFile(fFid);
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}
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void WAVAudioFileSource::doGetNextFrame() {
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if (feof(fFid) || ferror(fFid) || (fLimitNumBytesToStream && fNumBytesToStream == 0)) {
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handleClosure();
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return;
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}
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fFrameSize = 0; // until it's set later
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#ifdef READ_FROM_FILES_SYNCHRONOUSLY
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doReadFromFile();
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#else
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if (!fHaveStartedReading) {
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// Await readable data from the file:
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envir().taskScheduler().turnOnBackgroundReadHandling(fileno(fFid),
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(TaskScheduler::BackgroundHandlerProc*)&fileReadableHandler, this);
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fHaveStartedReading = True;
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}
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#endif
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}
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void WAVAudioFileSource::doStopGettingFrames() {
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envir().taskScheduler().unscheduleDelayedTask(nextTask());
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#ifndef READ_FROM_FILES_SYNCHRONOUSLY
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envir().taskScheduler().turnOffBackgroundReadHandling(fileno(fFid));
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fHaveStartedReading = False;
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#endif
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}
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void WAVAudioFileSource::fileReadableHandler(WAVAudioFileSource* source, int /*mask*/) {
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if (!source->isCurrentlyAwaitingData()) {
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source->doStopGettingFrames(); // we're not ready for the data yet
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return;
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}
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source->doReadFromFile();
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}
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void WAVAudioFileSource::doReadFromFile() {
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// Try to read as many bytes as will fit in the buffer provided (or "fPreferredFrameSize" if less)
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if (fLimitNumBytesToStream && fNumBytesToStream < fMaxSize) {
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fMaxSize = fNumBytesToStream;
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}
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if (fPreferredFrameSize < fMaxSize) {
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fMaxSize = fPreferredFrameSize;
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}
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unsigned bytesPerSample = (fNumChannels*fBitsPerSample)/8;
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if (bytesPerSample == 0) bytesPerSample = 1; // because we can't read less than a byte at a time
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// For 'trick play', read one sample at a time; otherwise (normal case) read samples in bulk:
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unsigned bytesToRead = fScaleFactor == 1 ? fMaxSize - fMaxSize%bytesPerSample : bytesPerSample;
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unsigned numBytesRead;
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while (1) { // loop for 'trick play' only
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#ifdef READ_FROM_FILES_SYNCHRONOUSLY
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numBytesRead = fread(fTo, 1, bytesToRead, fFid);
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#else
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if (fFidIsSeekable) {
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numBytesRead = fread(fTo, 1, bytesToRead, fFid);
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} else {
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// For non-seekable files (e.g., pipes), call "read()" rather than "fread()", to ensure that the read doesn't block:
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numBytesRead = read(fileno(fFid), fTo, bytesToRead);
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}
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#endif
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if (numBytesRead == 0) {
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handleClosure();
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return;
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}
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fFrameSize += numBytesRead;
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fTo += numBytesRead;
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fMaxSize -= numBytesRead;
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fNumBytesToStream -= numBytesRead;
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// If we did an asynchronous read, and didn't read an integral number of samples, then we need to wait for another read:
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#ifndef READ_FROM_FILES_SYNCHRONOUSLY
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if (fFrameSize%bytesPerSample > 0) return;
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#endif
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// If we're doing 'trick play', then seek to the appropriate place for reading the next sample,
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// and keep reading until we fill the provided buffer:
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if (fScaleFactor != 1) {
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SeekFile64(fFid, (fScaleFactor-1)*bytesPerSample, SEEK_CUR);
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if (fMaxSize < bytesPerSample) break;
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} else {
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break; // from the loop (normal case)
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}
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}
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// Set the 'presentation time' and 'duration' of this frame:
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if (fPresentationTime.tv_sec == 0 && fPresentationTime.tv_usec == 0) {
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// This is the first frame, so use the current time:
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gettimeofday(&fPresentationTime, NULL);
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} else {
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// Increment by the play time of the previous data:
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unsigned uSeconds = fPresentationTime.tv_usec + fLastPlayTime;
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fPresentationTime.tv_sec += uSeconds/1000000;
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fPresentationTime.tv_usec = uSeconds%1000000;
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}
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// Remember the play time of this data:
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fDurationInMicroseconds = fLastPlayTime
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= (unsigned)((fPlayTimePerSample*fFrameSize)/bytesPerSample);
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// Inform the reader that he has data:
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#ifdef READ_FROM_FILES_SYNCHRONOUSLY
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// To avoid possible infinite recursion, we need to return to the event loop to do this:
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nextTask() = envir().taskScheduler().scheduleDelayedTask(0,
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(TaskFunc*)FramedSource::afterGetting, this);
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#else
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// Because the file read was done from the event loop, we can call the
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// 'after getting' function directly, without risk of infinite recursion:
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FramedSource::afterGetting(this);
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#endif
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}
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Boolean WAVAudioFileSource::setInputPort(int /*portIndex*/) {
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return True;
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}
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double WAVAudioFileSource::getAverageLevel() const {
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return 0.0;//##### fix this later
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}
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