| /* |
| * 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 int get_format_from_sample_fmt(const char **fmt, |
| enum AVSampleFormat sample_fmt) |
| { |
| int i; |
| struct sample_fmt_entry { |
| enum AVSampleFormat sample_fmt; const char *fmt_be, *fmt_le; |
| } sample_fmt_entries[] = { |
| { AV_SAMPLE_FMT_U8, "u8", "u8" }, |
| { AV_SAMPLE_FMT_S16, "s16be", "s16le" }, |
| { AV_SAMPLE_FMT_S32, "s32be", "s32le" }, |
| { AV_SAMPLE_FMT_FLT, "f32be", "f32le" }, |
| { AV_SAMPLE_FMT_DBL, "f64be", "f64le" }, |
| }; |
| *fmt = NULL; |
| |
| for (i = 0; i < FF_ARRAY_ELEMS(sample_fmt_entries); i++) { |
| struct sample_fmt_entry *entry = &sample_fmt_entries[i]; |
| if (sample_fmt == entry->sample_fmt) { |
| *fmt = AV_NE(entry->fmt_be, entry->fmt_le); |
| return 0; |
| } |
| } |
| |
| fprintf(stderr, |
| "sample format %s is not supported as output format\n", |
| av_get_sample_fmt_name(sample_fmt)); |
| return -1; |
| } |
| |
| 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; |
| enum AVSampleFormat sfmt; |
| int n_channels = 0; |
| const char *fmt; |
| |
| if (argc <= 2) { |
| fprintf(stderr, "Usage: %s <input file> <output file>\n", argv[0]); |
| exit(0); |
| } |
| filename = argv[1]; |
| outfilename = argv[2]; |
| |
| 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); |
| |
| /* print output pcm infomations, because there have no metadata of pcm */ |
| sfmt = c->sample_fmt; |
| |
| if (av_sample_fmt_is_planar(sfmt)) { |
| const char *packed = av_get_sample_fmt_name(sfmt); |
| printf("Warning: the sample format the decoder produced is planar " |
| "(%s). This example will output the first channel only.\n", |
| packed ? packed : "?"); |
| sfmt = av_get_packed_sample_fmt(sfmt); |
| } |
| |
| n_channels = c->channels; |
| if ((ret = get_format_from_sample_fmt(&fmt, sfmt)) < 0) |
| goto end; |
| |
| printf("Play the output audio file with the command:\n" |
| "ffplay -f %s -ac %d -ar %d %s\n", |
| fmt, n_channels, c->sample_rate, |
| outfilename); |
| end: |
| fclose(outfile); |
| fclose(f); |
| |
| avcodec_free_context(&c); |
| av_parser_close(parser); |
| av_frame_free(&decoded_frame); |
| av_packet_free(&pkt); |
| |
| return 0; |
| } |