FFmpeg: libavfilter/asrc_aevalsrc.c Source File

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libavfilter

asrc_aevalsrc.c

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1 /*

3 *

4 * This file is part of FFmpeg.

5 *

6 * FFmpeg is free software; you can redistribute it and/or

7 * modify it under the terms of the GNU Lesser General Public

8 * License as published by the Free Software Foundation; either

9 * version 2.1 of the License, or (at your option) any later version.

10 *

11 * FFmpeg is distributed in the hope that it will be useful,

12 * but WITHOUT ANY WARRANTY; without even the implied warranty of

13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

14 * Lesser General Public License for more details.

15 *

16 * You should have received a copy of the GNU Lesser General Public

17 * License along with FFmpeg; if not, write to the Free Software

18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

19 */

21 /**

22 * @file

23 * eval audio source

24 */

26 #include "libavutil/avassert.h"

27 #include "libavutil/avstring.h"

28 #include "libavutil/channel_layout.h"

29 #include "libavutil/eval.h"

30 #include "libavutil/opt.h"

31 #include "libavutil/parseutils.h"

32 #include "avfilter.h"

33 #include "audio.h"

34 #include "internal.h"

36 static const char * const var_names[] = {

37 "n", ///< number of frame

38 "t", ///< timestamp expressed in seconds

39 "s", ///< sample rate

40 NULL

41 };

43 enum var_name {

44 VAR_N,

45 VAR_T,

46 VAR_S,

47 VAR_VARS_NB

48 };

50 typedef struct {

51 const AVClass *class;

52 char *sample_rate_str;

53 int sample_rate;

54 int64_t chlayout;

55 char *chlayout_str;

56 int nb_channels;

57 int64_t pts;

58 AVExpr *expr[8];

59 char *exprs;

60 int nb_samples; ///< number of samples per requested frame

61 char *duration_str; ///< total duration of the generated audio

62 double duration;

63 uint64_t n;

64 double var_values[VAR_VARS_NB];

65 } EvalContext;

67 #define OFFSET(x) offsetof(EvalContext, x)

68 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

70 static const AVOption aevalsrc_options[]= {

71 { "exprs", "set the '|'-separated list of channels expressions", OFFSET(exprs), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },

72 { "nb_samples", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },

73 { "n", "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 0, INT_MAX, FLAGS },

74 { "sample_rate", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },

75 { "s", "set the sample rate", OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },

76 { "duration", "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },

77 { "d", "set audio duration", OFFSET(duration_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },

78 { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },

79 { "c", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },

80 {NULL},

81 };

83 AVFILTER_DEFINE_CLASS(aevalsrc);

85 static int init(AVFilterContext *ctx)

86 {

87 EvalContext *eval = ctx->priv;

88 char *args1 = av_strdup(eval->exprs);

89 char *expr, *buf;

90 int ret, i;

92 if (!args1) {

93 av_log(ctx, AV_LOG_ERROR, "Channels expressions list is empty\n");

94 ret = eval->exprs ? AVERROR(ENOMEM) : AVERROR(EINVAL);

95 goto end;

96 }

98 /* parse expressions */

99 buf = args1;

100 i = 0;

101 while (i < FF_ARRAY_ELEMS(eval->expr) && (expr = av_strtok(buf, "|", &buf))) {

102 ret = av_expr_parse(&eval->expr[i], expr, var_names,

103 NULL, NULL, NULL, NULL, 0, ctx);

104 if (ret < 0)

105 goto end;

106 i++;

107 }

108 eval->nb_channels = i;

109

110 if (eval->chlayout_str) {

111 int n;

112 ret = ff_parse_channel_layout(&eval->chlayout, eval->chlayout_str, ctx);

113 if (ret < 0)

114 goto end;

115

116 n = av_get_channel_layout_nb_channels(eval->chlayout);

117 if (n != eval->nb_channels) {

118 av_log(ctx, AV_LOG_ERROR,

119 "Mismatch between the specified number of channels '%d' "

120 "and the number of channels '%d' in the specified channel layout '%s'\n",

121 eval->nb_channels, n, eval->chlayout_str);

122 ret = AVERROR(EINVAL);

123 goto end;

124 }

125 } else {

126 /* guess channel layout from nb expressions/channels */

127 eval->chlayout = av_get_default_channel_layout(eval->nb_channels);

128 if (!eval->chlayout) {

129 av_log(ctx, AV_LOG_ERROR, "Invalid number of channels '%d' provided\n",

130 eval->nb_channels);

131 ret = AVERROR(EINVAL);

132 goto end;

133 }

134 }

135

136 if ((ret = ff_parse_sample_rate(&eval->sample_rate, eval->sample_rate_str, ctx)))

137 goto end;

138

139 eval->duration = -1;

140 if (eval->duration_str) {

141 int64_t us = -1;

142 if ((ret = av_parse_time(&us, eval->duration_str, 1)) < 0) {

143 av_log(ctx, AV_LOG_ERROR, "Invalid duration: '%s'\n", eval->duration_str);

144 goto end;

145 }

146 eval->duration = (double)us / 1000000;

147 }

148 eval->n = 0;

149

150 end:

151 av_free(args1);

152 return ret;

153 }

154

155 static av_cold void uninit(AVFilterContext *ctx)

156 {

157 EvalContext *eval = ctx->priv;

158 int i;

159

160 for (i = 0; i < 8; i++) {

161 av_expr_free(eval->expr[i]);

162 eval->expr[i] = NULL;

163 }

164 av_freep(&eval->chlayout_str);

165 av_freep(&eval->duration_str);

166 av_freep(&eval->sample_rate_str);

167 }

168

169 static int config_props(AVFilterLink *outlink)

170 {

171 EvalContext *eval = outlink->src->priv;

172 char buf[128];

173

174 outlink->time_base = (AVRational){1, eval->sample_rate};

175 outlink->sample_rate = eval->sample_rate;

176

177 eval->var_values[VAR_S] = eval->sample_rate;

178

179 av_get_channel_layout_string(buf, sizeof(buf), 0, eval->chlayout);

180

181 av_log(outlink->src, AV_LOG_VERBOSE,

182 "sample_rate:%d chlayout:%s duration:%f\n",

183 eval->sample_rate, buf, eval->duration);

184

185 return 0;

186 }

187

188 static int query_formats(AVFilterContext *ctx)

189 {

190 EvalContext *eval = ctx->priv;

191 static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE };

192 int64_t chlayouts[] = { eval->chlayout, -1 };

193 int sample_rates[] = { eval->sample_rate, -1 };

194

195 ff_set_common_formats (ctx, ff_make_format_list(sample_fmts));

196 ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts));

197 ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates));

198

199 return 0;

200 }

201

202 static int request_frame(AVFilterLink *outlink)

203 {

204 EvalContext *eval = outlink->src->priv;

205 AVFrame *samplesref;

206 int i, j;

207 double t = eval->n * (double)1/eval->sample_rate;

208

209 if (eval->duration >= 0 && t >= eval->duration)

210 return AVERROR_EOF;

211

212 samplesref = ff_get_audio_buffer(outlink, eval->nb_samples);

213 if (!samplesref)

214 return AVERROR(ENOMEM);

215

216 /* evaluate expression for each single sample and for each channel */

217 for (i = 0; i < eval->nb_samples; i++, eval->n++) {

218 eval->var_values[VAR_N] = eval->n;

219 eval->var_values[VAR_T] = eval->var_values[VAR_N] * (double)1/eval->sample_rate;

220

221 for (j = 0; j < eval->nb_channels; j++) {

222 *((double *) samplesref->extended_data[j] + i) =

223 av_expr_eval(eval->expr[j], eval->var_values, NULL);

224 }

225 }

226

227 samplesref->pts = eval->pts;

228 samplesref->sample_rate = eval->sample_rate;

229 eval->pts += eval->nb_samples;

230

231 return ff_filter_frame(outlink, samplesref);

232 }

233

234 static const AVFilterPad aevalsrc_outputs[] = {

235 {

236 .name = "default",

237 .type = AVMEDIA_TYPE_AUDIO,

238 .config_props = config_props,

239 .request_frame = request_frame,

240 },

241 { NULL }

242 };

243

244 AVFilter avfilter_asrc_aevalsrc = {

245 .name = "aevalsrc",

246 .description = NULL_IF_CONFIG_SMALL("Generate an audio signal generated by an expression."),

247

248 .query_formats = query_formats,

249 .init = init,

250 .uninit = uninit,

251 .priv_size = sizeof(EvalContext),

252 .inputs = NULL,

253 .outputs = aevalsrc_outputs,

254 .priv_class = &aevalsrc_class,

255 };

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