FFmpeg: libavfilter/vf_fps.c Source File

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libavfilter

vf_fps.c

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1 /*

5 *

6 * This file is part of FFmpeg.

7 *

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

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

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

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

12 *

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

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

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

16 * Lesser General Public License for more details.

17 *

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

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

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

21 */

23 /**

24 * @file

25 * a filter enforcing given constant framerate

26 */

28 #include <float.h>

29 #include <stdint.h>

31 #include "libavutil/common.h"

32 #include "libavutil/fifo.h"

33 #include "libavutil/mathematics.h"

34 #include "libavutil/opt.h"

35 #include "libavutil/parseutils.h"

37 #include "avfilter.h"

38 #include "internal.h"

39 #include "video.h"

41 typedef struct FPSContext {

42 const AVClass *class;

44 AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps

46 /* timestamps in input timebase */

47 int64_t first_pts; ///< pts of the first frame that arrived on this filter

49 double start_time; ///< pts, in seconds, of the expected first frame

51 AVRational framerate; ///< target framerate

52 int rounding; ///< AVRounding method for timestamps

54 /* statistics */

55 int frames_in; ///< number of frames on input

56 int frames_out; ///< number of frames on output

57 int dup; ///< number of frames duplicated

58 int drop; ///< number of framed dropped

59 } FPSContext;

61 #define OFFSET(x) offsetof(FPSContext, x)

62 #define V AV_OPT_FLAG_VIDEO_PARAM

63 #define F AV_OPT_FLAG_FILTERING_PARAM

64 static const AVOption fps_options[] = {

65 { "fps", "A string describing desired output framerate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, { .str = "25" }, .flags = V|F },

66 { "start_time", "Assume the first PTS should be this value.", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX}, -DBL_MAX, DBL_MAX, V },

67 { "round", "set rounding method for timestamps", OFFSET(rounding), AV_OPT_TYPE_INT, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },

68 { "zero", "round towards 0", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_ZERO }, 0, 5, V|F, "round" },

69 { "inf", "round away from 0", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_INF }, 0, 5, V|F, "round" },

70 { "down", "round towards -infty", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_DOWN }, 0, 5, V|F, "round" },

71 { "up", "round towards +infty", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_UP }, 0, 5, V|F, "round" },

72 { "near", "round to nearest", OFFSET(rounding), AV_OPT_TYPE_CONST, { .i64 = AV_ROUND_NEAR_INF }, 0, 5, V|F, "round" },

73 { NULL }

74 };

76 AVFILTER_DEFINE_CLASS(fps);

78 static av_cold int init(AVFilterContext *ctx)

79 {

80 FPSContext *s = ctx->priv;

82 if (!(s->fifo = av_fifo_alloc_array(2, sizeof(AVFrame*))))

83 return AVERROR(ENOMEM);

85 s->first_pts = AV_NOPTS_VALUE;

87 av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);

88 return 0;

89 }

91 static void flush_fifo(AVFifoBuffer *fifo)

92 {

93 while (av_fifo_size(fifo)) {

94 AVFrame *tmp;

95 av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);

96 av_frame_free(&tmp);

97 }

98 }

100 static av_cold void uninit(AVFilterContext *ctx)

101 {

102 FPSContext *s = ctx->priv;

103 if (s->fifo) {

104 s->drop += av_fifo_size(s->fifo) / sizeof(AVFrame*);

105 flush_fifo(s->fifo);

106 av_fifo_freep(&s->fifo);

107 }

108

109 av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "

110 "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);

111 }

112

113 static int config_props(AVFilterLink* link)

114 {

115 FPSContext *s = link->src->priv;

116

117 link->time_base = av_inv_q(s->framerate);

118 link->frame_rate= s->framerate;

119 link->w = link->src->inputs[0]->w;

120 link->h = link->src->inputs[0]->h;

121

122 return 0;

123 }

124

125 static int request_frame(AVFilterLink *outlink)

126 {

127 AVFilterContext *ctx = outlink->src;

128 FPSContext *s = ctx->priv;

129 int frames_out = s->frames_out;

130 int ret = 0;

131

132 while (ret >= 0 && s->frames_out == frames_out)

133 ret = ff_request_frame(ctx->inputs[0]);

134

135 /* flush the fifo */

136 if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {

137 int i;

138 for (i = 0; av_fifo_size(s->fifo); i++) {

139 AVFrame *buf;

140

141 av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);

142 buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,

143 outlink->time_base) + s->frames_out;

144

145 if ((ret = ff_filter_frame(outlink, buf)) < 0)

146 return ret;

147

148 s->frames_out++;

149 }

150 return 0;

151 }

152

153 return ret;

154 }

155

156 static int write_to_fifo(AVFifoBuffer *fifo, AVFrame *buf)

157 {

158 int ret;

159

160 if (!av_fifo_space(fifo) &&

161 (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) {

162 av_frame_free(&buf);

163 return ret;

164 }

165

166 av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);

167 return 0;

168 }

169

170 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)

171 {

172 AVFilterContext *ctx = inlink->dst;

173 FPSContext *s = ctx->priv;

174 AVFilterLink *outlink = ctx->outputs[0];

175 int64_t delta;

176 int i, ret;

177

178 s->frames_in++;

179 /* discard frames until we get the first timestamp */

180 if (s->first_pts == AV_NOPTS_VALUE) {

181 if (buf->pts != AV_NOPTS_VALUE) {

182 ret = write_to_fifo(s->fifo, buf);

183 if (ret < 0)

184 return ret;

185

186 if (s->start_time != DBL_MAX && s->start_time != AV_NOPTS_VALUE) {

187 double first_pts = s->start_time * AV_TIME_BASE;

188 first_pts = FFMIN(FFMAX(first_pts, INT64_MIN), INT64_MAX);

189 s->first_pts = av_rescale_q(first_pts, AV_TIME_BASE_Q,

190 inlink->time_base);

191 av_log(ctx, AV_LOG_VERBOSE, "Set first pts to (in:%"PRId64" out:%"PRId64")\n",

192 s->first_pts, av_rescale_q(first_pts, AV_TIME_BASE_Q,

193 outlink->time_base));

194 } else {

195 s->first_pts = buf->pts;

196 }

197 } else {

198 av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "

199 "timestamp.\n");

200 av_frame_free(&buf);

201 s->drop++;

202 }

203 return 0;

204 }

205

206 /* now wait for the next timestamp */

207 if (buf->pts == AV_NOPTS_VALUE || av_fifo_size(s->fifo) <= 0) {

208 return write_to_fifo(s->fifo, buf);

209 }

210

211 /* number of output frames */

212 delta = av_rescale_q_rnd(buf->pts - s->first_pts, inlink->time_base,

213 outlink->time_base, s->rounding) - s->frames_out ;

214

215 if (delta < 1) {

216 /* drop everything buffered except the last */

217 int drop = av_fifo_size(s->fifo)/sizeof(AVFrame*);

218

219 av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);

220 s->drop += drop;

221

222 flush_fifo(s->fifo);

223 ret = write_to_fifo(s->fifo, buf);

224

225 return ret;

226 }

227

228 /* can output >= 1 frames */

229 for (i = 0; i < delta; i++) {

230 AVFrame *buf_out;

231 av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);

232

233 /* duplicate the frame if needed */

234 if (!av_fifo_size(s->fifo) && i < delta - 1) {

235 AVFrame *dup = av_frame_clone(buf_out);

236

237 av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");

238 if (dup)

239 ret = write_to_fifo(s->fifo, dup);

240 else

241 ret = AVERROR(ENOMEM);

242

243 if (ret < 0) {

244 av_frame_free(&buf_out);

245 av_frame_free(&buf);

246 return ret;

247 }

248

249 s->dup++;

250 }

251

252 buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,

253 outlink->time_base) + s->frames_out;

254

255 if ((ret = ff_filter_frame(outlink, buf_out)) < 0) {

256 av_frame_free(&buf);

257 return ret;

258 }

259

260 s->frames_out++;

261 }

262 flush_fifo(s->fifo);

263

264 ret = write_to_fifo(s->fifo, buf);

265

266 return ret;

267 }

268

269 static const AVFilterPad avfilter_vf_fps_inputs[] = {

270 {

271 .name = "default",

272 .type = AVMEDIA_TYPE_VIDEO,

273 .filter_frame = filter_frame,

274 },

275 { NULL }

276 };

277

278 static const AVFilterPad avfilter_vf_fps_outputs[] = {

279 {

280 .name = "default",

281 .type = AVMEDIA_TYPE_VIDEO,

282 .request_frame = request_frame,

283 .config_props = config_props

284 },

285 { NULL }

286 };

287

288 AVFilter ff_vf_fps = {

289 .name = "fps",

290 .description = NULL_IF_CONFIG_SMALL("Force constant framerate."),

291 .init = init,

292 .uninit = uninit,

293 .priv_size = sizeof(FPSContext),

294 .priv_class = &fps_class,

295 .inputs = avfilter_vf_fps_inputs,

296 .outputs = avfilter_vf_fps_outputs,

297 };

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