/* * Copyright (c) 2001 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ /** * @file * audio decoding with libavcodec API example * * @example decode_audio.c */ #include <stdio.h>#include <stdlib.h>#include <string.h> #include <libavutil/frame.h>#include <libavutil/mem.h> #include <libavcodec/avcodec.h> #define AUDIO_INBUF_SIZE 20480#define AUDIO_REFILL_THRESH 4096 static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame,                   FILE *outfile){    int i, ch;    int ret, data_size;     /* send the packet with the compressed data to the decoder */    ret = avcodec_send_packet(dec_ctx, pkt);    if (ret < 0) {        fprintf(stderr, "Error submitting the packet to the decoder\n");        exit(1);    }     /* read all the output frames (in general there may be any number of them */    while (ret >= 0) {        ret = avcodec_receive_frame(dec_ctx, frame);        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)            return;        else if (ret < 0) {            fprintf(stderr, "Error during decoding\n");            exit(1);        }        data_size = av_get_bytes_per_sample(dec_ctx->sample_fmt);        if (data_size < 0) {            /* This should not occur, checking just for paranoia */            fprintf(stderr, "Failed to calculate data size\n");            exit(1);        }        for (i = 0; i < frame->nb_samples; i++)            for (ch = 0; ch < dec_ctx->channels; ch++)                fwrite(frame->data[ch] + data_size*i, 1, data_size, outfile);    }} int main(int argc, char **argv){    const char *outfilename, *filename;    const AVCodec *codec;    AVCodecContext *c= NULL;    AVCodecParserContext *parser = NULL;    int len, ret;    FILE *f, *outfile;    uint8_t inbuf[AUDIO_INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];    uint8_t *data;    size_t   data_size;    AVPacket *pkt;    AVFrame *decoded_frame = NULL;     if (argc <= 2) {        fprintf(stderr, "Usage: %s <input file> <output file>\n", argv[0]);        exit(0);    }    filename    = argv[1];    outfilename = argv[2];     /* register all the codecs */    avcodec_register_all();     pkt = av_packet_alloc();     /* find the MPEG audio decoder */    codec = avcodec_find_decoder(AV_CODEC_ID_MP2);    if (!codec) {        fprintf(stderr, "Codec not found\n");        exit(1);    }     parser = av_parser_init(codec->id);    if (!parser) {        fprintf(stderr, "Parser not found\n");        exit(1);    }     c = avcodec_alloc_context3(codec);    if (!c) {        fprintf(stderr, "Could not allocate audio codec context\n");        exit(1);    }     /* open it */    if (avcodec_open2(c, codec, NULL) < 0) {        fprintf(stderr, "Could not open codec\n");        exit(1);    }     f = fopen(filename, "rb");    if (!f) {        fprintf(stderr, "Could not open %s\n", filename);        exit(1);    }    outfile = fopen(outfilename, "wb");    if (!outfile) {        av_free(c);        exit(1);    }     /* decode until eof */    data      = inbuf;    data_size = fread(inbuf, 1, AUDIO_INBUF_SIZE, f);     while (data_size > 0) {        if (!decoded_frame) {            if (!(decoded_frame = av_frame_alloc())) {                fprintf(stderr, "Could not allocate audio frame\n");                exit(1);            }        }         ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size,                               data, data_size,                               AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0);        if (ret < 0) {            fprintf(stderr, "Error while parsing\n");            exit(1);        }        data      += ret;        data_size -= ret;         if (pkt->size)            decode(c, pkt, decoded_frame, outfile);         if (data_size < AUDIO_REFILL_THRESH) {            memmove(inbuf, data, data_size);            data = inbuf;            len = fread(data + data_size, 1,                        AUDIO_INBUF_SIZE - data_size, f);            if (len > 0)                data_size += len;        }    }     /* flush the decoder */    pkt->data = NULL;    pkt->size = 0;    decode(c, pkt, decoded_frame, outfile);     fclose(outfile);    fclose(f);     avcodec_free_context(&c);    av_parser_close(parser);    av_frame_free(&decoded_frame);    av_packet_free(&pkt);     return 0;}