1/* 2 * Copyright (c) 2010 Nicolas George 3 * Copyright (c) 2011 Stefano Sabatini 4 * Copyright (c) 2012 Cl��ment B��sch 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 25/** 26 * @file 27 * API example for audio decoding and filtering 28 * @example filtering_audio.c 29 */ 30 31#include <unistd.h> 32 33#include <libavcodec/avcodec.h> 34#include <libavformat/avformat.h> 35#include <libavfilter/avfiltergraph.h> 36#include <libavfilter/avcodec.h> 37#include <libavfilter/buffersink.h> 38#include <libavfilter/buffersrc.h> 39#include <libavutil/opt.h> 40 41static const char *filter_descr = "aresample=8000,aformat=sample_fmts=s16:channel_layouts=mono"; 42static const char *player = "ffplay -f s16le -ar 8000 -ac 1 -"; 43 44static AVFormatContext *fmt_ctx; 45static AVCodecContext *dec_ctx; 46AVFilterContext *buffersink_ctx; 47AVFilterContext *buffersrc_ctx; 48AVFilterGraph *filter_graph; 49static int audio_stream_index = -1; 50 51static int open_input_file(const char *filename) 52{ 53 int ret; 54 AVCodec *dec; 55 56 if ((ret = avformat_open_input(&fmt_ctx, filename, NULL, NULL)) < 0) { 57 av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n"); 58 return ret; 59 } 60 61 if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) < 0) { 62 av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n"); 63 return ret; 64 } 65 66 /* select the audio stream */ 67 ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_AUDIO, -1, -1, &dec, 0); 68 if (ret < 0) { 69 av_log(NULL, AV_LOG_ERROR, "Cannot find a audio stream in the input file\n"); 70 return ret; 71 } 72 audio_stream_index = ret; 73 dec_ctx = fmt_ctx->streams[audio_stream_index]->codec; 74 av_opt_set_int(dec_ctx, "refcounted_frames", 1, 0); 75 76 /* init the audio decoder */ 77 if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) { 78 av_log(NULL, AV_LOG_ERROR, "Cannot open audio decoder\n"); 79 return ret; 80 } 81 82 return 0; 83} 84 85static int init_filters(const char *filters_descr) 86{ 87 char args[512]; 88 int ret = 0; 89 AVFilter *abuffersrc = avfilter_get_by_name("abuffer"); 90 AVFilter *abuffersink = avfilter_get_by_name("abuffersink"); 91 AVFilterInOut *outputs = avfilter_inout_alloc(); 92 AVFilterInOut *inputs = avfilter_inout_alloc(); 93 static const enum AVSampleFormat out_sample_fmts[] = { AV_SAMPLE_FMT_S16, -1 }; 94 static const int64_t out_channel_layouts[] = { AV_CH_LAYOUT_MONO, -1 }; 95 static const int out_sample_rates[] = { 8000, -1 }; 96 const AVFilterLink *outlink; 97 AVRational time_base = fmt_ctx->streams[audio_stream_index]->time_base; 98 99 filter_graph = avfilter_graph_alloc(); 100 if (!outputs || !inputs || !filter_graph) { 101 ret = AVERROR(ENOMEM); 102 goto end; 103 } 104 105 /* buffer audio source: the decoded frames from the decoder will be inserted here. */ 106 if (!dec_ctx->channel_layout) 107 dec_ctx->channel_layout = av_get_default_channel_layout(dec_ctx->channels); 108 snprintf(args, sizeof(args), 109 "time_base=%d/%d:sample_rate=%d:sample_fmt=%s:channel_layout=0x%"PRIx64, 110 time_base.num, time_base.den, dec_ctx->sample_rate, 111 av_get_sample_fmt_name(dec_ctx->sample_fmt), dec_ctx->channel_layout); 112 ret = avfilter_graph_create_filter(&buffersrc_ctx, abuffersrc, "in", 113 args, NULL, filter_graph); 114 if (ret < 0) { 115 av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer source\n"); 116 goto end; 117 } 118 119 /* buffer audio sink: to terminate the filter chain. */ 120 ret = avfilter_graph_create_filter(&buffersink_ctx, abuffersink, "out", 121 NULL, NULL, filter_graph); 122 if (ret < 0) { 123 av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer sink\n"); 124 goto end; 125 } 126 127 ret = av_opt_set_int_list(buffersink_ctx, "sample_fmts", out_sample_fmts, -1, 128 AV_OPT_SEARCH_CHILDREN); 129 if (ret < 0) { 130 av_log(NULL, AV_LOG_ERROR, "Cannot set output sample format\n"); 131 goto end; 132 } 133 134 ret = av_opt_set_int_list(buffersink_ctx, "channel_layouts", out_channel_layouts, -1, 135 AV_OPT_SEARCH_CHILDREN); 136 if (ret < 0) { 137 av_log(NULL, AV_LOG_ERROR, "Cannot set output channel layout\n"); 138 goto end; 139 } 140 141 ret = av_opt_set_int_list(buffersink_ctx, "sample_rates", out_sample_rates, -1, 142 AV_OPT_SEARCH_CHILDREN); 143 if (ret < 0) { 144 av_log(NULL, AV_LOG_ERROR, "Cannot set output sample rate\n"); 145 goto end; 146 } 147 148 /* Endpoints for the filter graph. */ 149 outputs->name = av_strdup("in"); 150 outputs->filter_ctx = buffersrc_ctx; 151 outputs->pad_idx = 0; 152 outputs->next = NULL; 153 154 inputs->name = av_strdup("out"); 155 inputs->filter_ctx = buffersink_ctx; 156 inputs->pad_idx = 0; 157 inputs->next = NULL; 158 159 if ((ret = avfilter_graph_parse_ptr(filter_graph, filters_descr, 160 &inputs, &outputs, NULL)) < 0) 161 goto end; 162 163 if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0) 164 goto end; 165 166 /* Print summary of the sink buffer 167 * Note: args buffer is reused to store channel layout string */ 168 outlink = buffersink_ctx->inputs[0]; 169 av_get_channel_layout_string(args, sizeof(args), -1, outlink->channel_layout); 170 av_log(NULL, AV_LOG_INFO, "Output: srate:%dHz fmt:%s chlayout:%s\n", 171 (int)outlink->sample_rate, 172 (char *)av_x_if_null(av_get_sample_fmt_name(outlink->format), "?"), 173 args); 174 175end: 176 avfilter_inout_free(&inputs); 177 avfilter_inout_free(&outputs); 178 179 return ret; 180} 181 182static void print_frame(const AVFrame *frame) 183{ 184 const int n = frame->nb_samples * av_get_channel_layout_nb_channels(av_frame_get_channel_layout(frame)); 185 const uint16_t *p = (uint16_t*)frame->data[0]; 186 const uint16_t *p_end = p + n; 187 188 while (p < p_end) { 189 fputc(*p & 0xff, stdout); 190 fputc(*p>>8 & 0xff, stdout); 191 p++; 192 } 193 fflush(stdout); 194} 195 196int main(int argc, char **argv) 197{ 198 int ret; 199 AVPacket packet0, packet; 200 AVFrame *frame = av_frame_alloc(); 201 AVFrame *filt_frame = av_frame_alloc(); 202 int got_frame; 203 204 if (!frame || !filt_frame) { 205 perror("Could not allocate frame"); 206 exit(1); 207 } 208 if (argc != 2) { 209 fprintf(stderr, "Usage: %s file | %s\n", argv[0], player); 210 exit(1); 211 } 212 213 av_register_all(); 214 avfilter_register_all(); 215 216 if ((ret = open_input_file(argv[1])) < 0) 217 goto end; 218 if ((ret = init_filters(filter_descr)) < 0) 219 goto end; 220 221 /* read all packets */ 222 packet0.data = NULL; 223 packet.data = NULL; 224 while (1) { 225 if (!packet0.data) { 226 if ((ret = av_read_frame(fmt_ctx, &packet)) < 0) 227 break; 228 packet0 = packet; 229 } 230 231 if (packet.stream_index == audio_stream_index) { 232 got_frame = 0; 233 ret = avcodec_decode_audio4(dec_ctx, frame, &got_frame, &packet); 234 if (ret < 0) { 235 av_log(NULL, AV_LOG_ERROR, "Error decoding audio\n"); 236 continue; 237 } 238 packet.size -= ret; 239 packet.data += ret; 240 241 if (got_frame) { 242 /* push the audio data from decoded frame into the filtergraph */ 243 if (av_buffersrc_add_frame_flags(buffersrc_ctx, frame, 0) < 0) { 244 av_log(NULL, AV_LOG_ERROR, "Error while feeding the audio filtergraph\n"); 245 break; 246 } 247 248 /* pull filtered audio from the filtergraph */ 249 while (1) { 250 ret = av_buffersink_get_frame(buffersink_ctx, filt_frame); 251 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) 252 break; 253 if (ret < 0) 254 goto end; 255 print_frame(filt_frame); 256 av_frame_unref(filt_frame); 257 } 258 } 259 260 if (packet.size <= 0) 261 av_free_packet(&packet0); 262 } else { 263 /* discard non-wanted packets */ 264 av_free_packet(&packet0); 265 } 266 } 267end: 268 avfilter_graph_free(&filter_graph); 269 avcodec_close(dec_ctx); 270 avformat_close_input(&fmt_ctx); 271 av_frame_free(&frame); 272 av_frame_free(&filt_frame); 273 274 if (ret < 0 && ret != AVERROR_EOF) { 275 fprintf(stderr, "Error occurred: %s\n", av_err2str(ret)); 276 exit(1); 277 } 278 279 exit(0); 280} 281