audio_encoder.cpp

MPEG-4编解码的实现(包括MPEG4视音频编解码)

/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (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.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is MPEG4IP.
 * 
 * The Initial Developer of the Original Code is Cisco Systems Inc.
 * Portions created by Cisco Systems Inc. are
 * Copyright (C) Cisco Systems Inc. 2000-2002.  All Rights Reserved.
 * 
 * Contributor(s): 
 *		Dave Mackie		[e-mail]
 */

#include "mp4live.h"
#include "audio_encoder.h"

#ifdef ADD_LAME_ENCODER
#include "audio_lame.h"
#endif

#ifdef ADD_FAAC_ENCODER
#include "audio_faac.h"
#endif


CAudioEncoder* AudioEncoderCreate(const char* encoderName)
{
	if (!strcasecmp(encoderName, AUDIO_ENCODER_FAAC)) {
#ifdef ADD_FAAC_ENCODER
		return new CFaacAudioEncoder();
#else
		error_message("faac encoder not available in this build");
		return false;
#endif
	} else if (!strcasecmp(encoderName, AUDIO_ENCODER_LAME)) {
#ifdef ADD_LAME_ENCODER
		return new CLameAudioEncoder();
#else
		error_message("lame encoder not available in this build");
#endif
	} else {
		error_message("unknown encoder specified");
	}
	return NULL;
}

bool CAudioEncoder::InterleaveStereoSamples(
	u_int16_t* pLeftBuffer, 
	u_int16_t* pRightBuffer, 
	u_int32_t srcNumSamples,
	u_int16_t** ppDstBuffer)
{
	if (*ppDstBuffer == NULL) {
		*ppDstBuffer = 
			(u_int16_t*)malloc(srcNumSamples * 2 * sizeof(u_int16_t));

		if (*ppDstBuffer == NULL) {
			return false;
		}
	}

	for (u_int32_t i = 0; i < srcNumSamples; i++) {
		(*ppDstBuffer)[(i << 1)] = pLeftBuffer[i]; 
		(*ppDstBuffer)[(i << 1) + 1] = pRightBuffer[i];
	}

	return true;
}

bool CAudioEncoder::DeinterleaveStereoSamples(
	u_int16_t* pSrcBuffer, 
	u_int32_t srcNumSamples,
	u_int16_t** ppLeftBuffer, 
	u_int16_t** ppRightBuffer)
{
	bool mallocedLeft = false;

	if (*ppLeftBuffer == NULL) {
		*ppLeftBuffer = 
			(u_int16_t*)malloc((srcNumSamples >> 1) * sizeof(u_int16_t));
		if (*ppLeftBuffer == NULL) {
			return false;
		}
		mallocedLeft = true;
	}

	if (*ppRightBuffer == NULL) {
		*ppRightBuffer = 
			(u_int16_t*)malloc((srcNumSamples >> 1) * sizeof(u_int16_t));
		if (*ppRightBuffer == NULL) {
			if (mallocedLeft) {
				free(*ppLeftBuffer);
				*ppLeftBuffer = NULL;
			}
			return false;
		}
	}

	for (u_int32_t i = 0; i < (srcNumSamples >> 1); i++) {
		(*ppLeftBuffer)[i] = pSrcBuffer[(i << 1)];
		(*ppRightBuffer)[i] = pSrcBuffer[(i << 1) + 1];
	}

	return true;
}