| 1 | /* |
| 2 | * Copyright (c) 2010 Nicolas George |
| 3 | * Copyright (c) 2011 Stefano Sabatini |
| 4 | * Copyright (c) 2012 Clément Bœsch |
| 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 | |
| 41 | static const char *filter_descr = "aresample=8000,aformat=sample_fmts=s16:channel_layouts=mono"; |
| 42 | static const char *player = "ffplay -f s16le -ar 8000 -ac 1 -"; |
| 43 | |
| 44 | static AVFormatContext *fmt_ctx; |
| 45 | static AVCodecContext *dec_ctx; |
| 46 | AVFilterContext *buffersink_ctx; |
| 47 | AVFilterContext *buffersrc_ctx; |
| 48 | AVFilterGraph *filter_graph; |
| 49 | static int audio_stream_index = -1; |
| 50 | |
| 51 | static 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 | |
| 85 | static 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 | |
| 175 | end: |
| 176 | avfilter_inout_free(&inputs); |
| 177 | avfilter_inout_free(&outputs); |
| 178 | |
| 179 | return ret; |
| 180 | } |
| 181 | |
| 182 | static 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 | |
| 196 | int 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 | } |
| 267 | end: |
| 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 | } |