/*jshint node:true*/
'use strict';
var spawn = require('child_process').spawn;
var path = require('path');
var fs = require('fs');
var async = require('async');
var utils = require('./utils');
var nlRegexp = /\r\n|\r|\n/g;
/*
*! Processor methods
*/
/**
* Run ffprobe asynchronously and store data in command
*
* @param {FfmpegCommand} command
* @private
*/
function runFfprobe(command) {
command.ffprobe(0, function(err, data) {
command._ffprobeData = data;
});
}
module.exports = function(proto) {
/**
* Emitted just after ffmpeg has been spawned.
*
* @event FfmpegCommand#start
* @param {String} command ffmpeg command line
*/
/**
* Emitted when ffmpeg reports progress information
*
* @event FfmpegCommand#progress
* @param {Object} progress progress object
* @param {Number} progress.frames number of frames transcoded
* @param {Number} progress.currentFps current processing speed in frames per second
* @param {Number} progress.currentKbps current output generation speed in kilobytes per second
* @param {Number} progress.targetSize current output file size
* @param {String} progress.timemark current video timemark
* @param {Number} [progress.percent] processing progress (may not be available depending on input)
*/
/**
* Emitted when ffmpeg outputs to stderr
*
* @event FfmpegCommand#stderr
* @param {String} line stderr output line
*/
/**
* Emitted when ffmpeg reports input codec data
*
* @event FfmpegCommand#codecData
* @param {Object} codecData codec data object
* @param {String} codecData.format input format name
* @param {String} codecData.audio input audio codec name
* @param {String} codecData.audio_details input audio codec parameters
* @param {String} codecData.video input video codec name
* @param {String} codecData.video_details input video codec parameters
*/
/**
* Emitted when an error happens when preparing or running a command
*
* @event FfmpegCommand#error
* @param {Error} error error object
* @param {String|null} stdout ffmpeg stdout, unless outputting to a stream
* @param {String|null} stderr ffmpeg stderr
*/
/**
* Emitted when a command finishes processing
*
* @event FfmpegCommand#end
* @param {Array|String|null} [filenames|stdout] generated filenames when taking screenshots, ffmpeg stdout when not outputting to a stream, null otherwise
* @param {String|null} stderr ffmpeg stderr
*/
/**
* Spawn an ffmpeg process
*
* The 'options' argument may contain the following keys:
* - 'niceness': specify process niceness, ignored on Windows (default: 0)
* - `cwd`: change working directory
* - 'captureStdout': capture stdout and pass it to 'endCB' as its 2nd argument (default: false)
* - 'stdoutLines': override command limit (default: use command limit)
*
* The 'processCB' callback, if present, is called as soon as the process is created and
* receives a nodejs ChildProcess object. It may not be called at all if an error happens
* before spawning the process.
*
* The 'endCB' callback is called either when an error occurs or when the ffmpeg process finishes.
*
* @method FfmpegCommand#_spawnFfmpeg
* @param {Array} args ffmpeg command line argument list
* @param {Object} [options] spawn options (see above)
* @param {Function} [processCB] callback called with process object and stdout/stderr ring buffers when process has been created
* @param {Function} endCB callback called with error (if applicable) and stdout/stderr ring buffers when process finished
* @private
*/
proto._spawnFfmpeg = function(args, options, processCB, endCB) {
// Enable omitting options
if (typeof options === 'function') {
endCB = processCB;
processCB = options;
options = {};
}
// Enable omitting processCB
if (typeof endCB === 'undefined') {
endCB = processCB;
processCB = function() {};
}
var maxLines = 'stdoutLines' in options ? options.stdoutLines : this.options.stdoutLines;
// Find ffmpeg
this._getFfmpegPath(function(err, command) {
if (err) {
return endCB(err);
} else if (!command || command.length === 0) {
return endCB(new Error('Cannot find ffmpeg'));
}
// Apply niceness
if (options.niceness && options.niceness !== 0 && !utils.isWindows) {
args.unshift('-n', options.niceness, command);
command = 'nice';
}
var stdoutRing = utils.linesRing(maxLines);
var stdoutClosed = false;
var stderrRing = utils.linesRing(maxLines);
var stderrClosed = false;
// Spawn process
var ffmpegProc = spawn(command, args, options);
if (ffmpegProc.stderr) {
ffmpegProc.stderr.setEncoding('utf8');
}
ffmpegProc.on('error', function(err) {
endCB(err);
});
// Ensure we wait for captured streams to end before calling endCB
var exitError = null;
function handleExit(err) {
if (err) {
exitError = err;
}
if (processExited && (stdoutClosed || !options.captureStdout) && stderrClosed) {
endCB(exitError, stdoutRing, stderrRing);
}
}
// Handle process exit
var processExited = false;
ffmpegProc.on('exit', function(code, signal) {
processExited = true;
if (signal) {
handleExit(new Error('ffmpeg was killed with signal ' + signal));
} else if (code) {
handleExit(new Error('ffmpeg exited with code ' + code));
} else {
handleExit();
}
});
// Capture stdout if specified
if (options.captureStdout) {
ffmpegProc.stdout.on('data', function(data) {
stdoutRing.append(data);
});
ffmpegProc.stdout.on('close', function() {
stdoutRing.close();
stdoutClosed = true;
handleExit();
});
}
// Capture stderr if specified
ffmpegProc.stderr.on('data', function(data) {
stderrRing.append(data);
});
ffmpegProc.stderr.on('close', function() {
stderrRing.close();
stderrClosed = true;
handleExit();
});
// Call process callback
processCB(ffmpegProc, stdoutRing, stderrRing);
});
};
/**
* Build the argument list for an ffmpeg command
*
* @method FfmpegCommand#_getArguments
* @return argument list
* @private
*/
proto._getArguments = function() {
var complexFilters = this._complexFilters.get();
var fileOutput = this._outputs.some(function(output) {
return output.isFile;
});
return [].concat(
// Inputs and input options
this._inputs.reduce(function(args, input) {
var source = (typeof input.source === 'string') ? input.source : 'pipe:0';
// For each input, add input options, then '-i <source>'
return args.concat(
input.options.get(),
['-i', source]
);
}, []),
// Global options
this._global.get(),
// Overwrite if we have file outputs
fileOutput ? ['-y'] : [],
// Complex filters
complexFilters,
// Outputs, filters and output options
this._outputs.reduce(function(args, output) {
var sizeFilters = utils.makeFilterStrings(output.sizeFilters.get());
var audioFilters = output.audioFilters.get();
var videoFilters = output.videoFilters.get().concat(sizeFilters);
var outputArg;
if (!output.target) {
outputArg = [];
} else if (typeof output.target === 'string') {
outputArg = [output.target];
} else {
outputArg = ['pipe:1'];
}
return args.concat(
output.audio.get(),
audioFilters.length ? ['-filter:a', audioFilters.join(',')] : [],
output.video.get(),
videoFilters.length ? ['-filter:v', videoFilters.join(',')] : [],
output.options.get(),
outputArg
);
}, [])
);
};
/**
* Prepare execution of an ffmpeg command
*
* Checks prerequisites for the execution of the command (codec/format availability, flvtool...),
* then builds the argument list for ffmpeg and pass them to 'callback'.
*
* @method FfmpegCommand#_prepare
* @param {Function} callback callback with signature (err, args)
* @param {Boolean} [readMetadata=false] read metadata before processing
* @private
*/
proto._prepare = function(callback, readMetadata) {
var self = this;
async.waterfall([
// Check codecs and formats
function(cb) {
self._checkCapabilities(cb);
},
// Read metadata if required
function(cb) {
if (!readMetadata) {
return cb();
}
self.ffprobe(0, function(err, data) {
if (!err) {
self._ffprobeData = data;
}
cb();
});
},
// Check for flvtool2/flvmeta if necessary
function(cb) {
var flvmeta = self._outputs.some(function(output) {
// Remove flvmeta flag on non-file output
if (output.flags.flvmeta && !output.isFile) {
self.logger.warn('Updating flv metadata is only supported for files');
output.flags.flvmeta = false;
}
return output.flags.flvmeta;
});
if (flvmeta) {
self._getFlvtoolPath(function(err) {
cb(err);
});
} else {
cb();
}
},
// Build argument list
function(cb) {
var args;
try {
args = self._getArguments();
} catch(e) {
return cb(e);
}
cb(null, args);
},
// Add "-strict experimental" option where needed
function(args, cb) {
self.availableEncoders(function(err, encoders) {
for (var i = 0; i < args.length; i++) {
if (args[i] === '-acodec' || args[i] === '-vcodec') {
i++;
if ((args[i] in encoders) && encoders[args[i]].experimental) {
args.splice(i + 1, 0, '-strict', 'experimental');
i += 2;
}
}
}
cb(null, args);
});
}
], callback);
if (!readMetadata) {
// Read metadata as soon as 'progress' listeners are added
if (this.listeners('progress').length > 0) {
// Read metadata in parallel
runFfprobe(this);
} else {
// Read metadata as soon as the first 'progress' listener is added
this.once('newListener', function(event) {
if (event === 'progress') {
runFfprobe(this);
}
});
}
}
};
/**
* Run ffmpeg command
*
* @method FfmpegCommand#run
* @category Processing
* @aliases exec,execute
*/
proto.exec =
proto.execute =
proto.run = function() {
var self = this;
// Check if at least one output is present
var outputPresent = this._outputs.some(function(output) {
return 'target' in output;
});
if (!outputPresent) {
throw new Error('No output specified');
}
// Get output stream if any
var outputStream = this._outputs.filter(function(output) {
return typeof output.target !== 'string';
})[0];
// Get input stream if any
var inputStream = this._inputs.filter(function(input) {
return typeof input.source !== 'string';
})[0];
// Ensure we send 'end' or 'error' only once
var ended = false;
function emitEnd(err, stdout, stderr) {
if (!ended) {
ended = true;
if (err) {
self.emit('error', err, stdout, stderr);
} else {
self.emit('end', stdout, stderr);
}
}
}
self._prepare(function(err, args) {
if (err) {
return emitEnd(err);
}
// Run ffmpeg
self._spawnFfmpeg(
args,
{
captureStdout: !outputStream,
niceness: self.options.niceness,
cwd: self.options.cwd
},
function processCB(ffmpegProc, stdoutRing, stderrRing) {
self.ffmpegProc = ffmpegProc;
self.emit('start', 'ffmpeg ' + args.join(' '));
// Pipe input stream if any
if (inputStream) {
inputStream.source.on('error', function(err) {
emitEnd(new Error('Input stream error: ' + err.message));
ffmpegProc.kill();
});
inputStream.source.resume();
inputStream.source.pipe(ffmpegProc.stdin);
// Set stdin error handler on ffmpeg (prevents nodejs catching the error, but
// ffmpeg will fail anyway, so no need to actually handle anything)
ffmpegProc.stdin.on('error', function() {});
}
// Setup timeout if requested
var processTimer;
if (self.options.timeout) {
processTimer = setTimeout(function() {
var msg = 'process ran into a timeout (' + self.options.timeout + 's)';
emitEnd(new Error(msg), stdoutRing.get(), stderrRing.get());
ffmpegProc.kill();
}, self.options.timeout * 1000);
}
if (outputStream) {
// Pipe ffmpeg stdout to output stream
ffmpegProc.stdout.pipe(outputStream.target, outputStream.pipeopts);
// Handle output stream events
outputStream.target.on('close', function() {
self.logger.debug('Output stream closed, scheduling kill for ffmpgeg process');
// Don't kill process yet, to give a chance to ffmpeg to
// terminate successfully first This is necessary because
// under load, the process 'exit' event sometimes happens
// after the output stream 'close' event.
setTimeout(function() {
emitEnd(new Error('Output stream closed'));
ffmpegProc.kill();
}, 20);
});
outputStream.target.on('error', function(err) {
self.logger.debug('Output stream error, killing ffmpgeg process');
emitEnd(new Error('Output stream error: ' + err.message), stdoutRing.get(), stderrRing.get());
ffmpegProc.kill();
});
}
// Setup stderr handling
if (stderrRing) {
// 'stderr' event
if (self.listeners('stderr').length) {
stderrRing.callback(function(line) {
self.emit('stderr', line);
});
}
// 'codecData' event
if (self.listeners('codecData').length) {
var codecDataSent = false;
var codecObject = {};
stderrRing.callback(function(line) {
if (!codecDataSent)
codecDataSent = utils.extractCodecData(self, line, codecObject);
});
}
// 'progress' event
if (self.listeners('progress').length) {
var duration = 0;
if (self._ffprobeData && self._ffprobeData.format && self._ffprobeData.format.duration) {
duration = Number(self._ffprobeData.format.duration);
}
stderrRing.callback(function(line) {
utils.extractProgress(self, line, duration);
});
}
}
},
function endCB(err, stdoutRing, stderrRing) {
delete self.ffmpegProc;
if (err) {
if (err.message.match(/ffmpeg exited with code/)) {
// Add ffmpeg error message
err.message += ': ' + utils.extractError(stderrRing.get());
}
emitEnd(err, stdoutRing.get(), stderrRing.get());
} else {
// Find out which outputs need flv metadata
var flvmeta = self._outputs.filter(function(output) {
return output.flags.flvmeta;
});
if (flvmeta.length) {
self._getFlvtoolPath(function(err, flvtool) {
if (err) {
return emitEnd(err);
}
async.each(
flvmeta,
function(output, cb) {
spawn(flvtool, ['-U', output.target])
.on('error', function(err) {
cb(new Error('Error running ' + flvtool + ' on ' + output.target + ': ' + err.message));
})
.on('exit', function(code, signal) {
if (code !== 0 || signal) {
cb(
new Error(flvtool + ' ' +
(signal ? 'received signal ' + signal
: 'exited with code ' + code)) +
' when running on ' + output.target
);
} else {
cb();
}
});
},
function(err) {
if (err) {
emitEnd(err);
} else {
emitEnd(null, stdoutRing.get(), stderrRing.get());
}
}
);
});
} else {
emitEnd(null, stdoutRing.get(), stderrRing.get());
}
}
}
);
});
};
/**
* Renice current and/or future ffmpeg processes
*
* Ignored on Windows platforms.
*
* @method FfmpegCommand#renice
* @category Processing
*
* @param {Number} [niceness=0] niceness value between -20 (highest priority) and 20 (lowest priority)
* @return FfmpegCommand
*/
proto.renice = function(niceness) {
if (!utils.isWindows) {
niceness = niceness || 0;
if (niceness < -20 || niceness > 20) {
this.logger.warn('Invalid niceness value: ' + niceness + ', must be between -20 and 20');
}
niceness = Math.min(20, Math.max(-20, niceness));
this.options.niceness = niceness;
if (this.ffmpegProc) {
var logger = this.logger;
var pid = this.ffmpegProc.pid;
var renice = spawn('renice', [niceness, '-p', pid]);
renice.on('error', function(err) {
logger.warn('could not renice process ' + pid + ': ' + err.message);
});
renice.on('exit', function(code, signal) {
if (signal) {
logger.warn('could not renice process ' + pid + ': renice was killed by signal ' + signal);
} else if (code) {
logger.warn('could not renice process ' + pid + ': renice exited with ' + code);
} else {
logger.info('successfully reniced process ' + pid + ' to ' + niceness + ' niceness');
}
});
}
}
return this;
};
/**
* Kill current ffmpeg process, if any
*
* @method FfmpegCommand#kill
* @category Processing
*
* @param {String} [signal=SIGKILL] signal name
* @return FfmpegCommand
*/
proto.kill = function(signal) {
if (!this.ffmpegProc) {
this.logger.warn('No running ffmpeg process, cannot send signal');
} else {
this.ffmpegProc.kill(signal || 'SIGKILL');
}
return this;
};
};