/* * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * a filter enforcing given constant framerate */ #include <float.h> #include <stdint.h> #include "libavutil/common.h" #include "libavutil/fifo.h" #include "libavutil/mathematics.h" #include "libavutil/opt.h" #include "libavutil/parseutils.h" #include "avfilter.h" #include "internal.h" #include "video.h" typedef struct FPSContext { const AVClass *class; AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps /* timestamps in input timebase */ int64_t first_pts; ///< pts of the first frame that arrived on this filter int64_t pts; ///< pts of the first frame currently in the fifo double start_time; ///< pts, in seconds, of the expected first frame AVRational framerate; ///< target framerate char *fps; ///< a string describing target framerate /* statistics */ int frames_in; ///< number of frames on input int frames_out; ///< number of frames on output int dup; ///< number of frames duplicated int drop; ///< number of framed dropped } FPSContext; #define OFFSET(x) offsetof(FPSContext, x) #define V AV_OPT_FLAG_VIDEO_PARAM static const AVOption options[] = { { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V }, { "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 }, { NULL }, }; static const AVClass class = { .class_name = "FPS filter", .item_name = av_default_item_name, .option = options, .version = LIBAVUTIL_VERSION_INT, }; static av_cold int init(AVFilterContext *ctx) { FPSContext *s = ctx->priv; int ret; if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) { av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps); return ret; } if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFrame*)))) return AVERROR(ENOMEM); s->pts = AV_NOPTS_VALUE; s->first_pts = AV_NOPTS_VALUE; av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den); return 0; } static void flush_fifo(AVFifoBuffer *fifo) { while (av_fifo_size(fifo)) { AVFrame *tmp; av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL); av_frame_free(&tmp); } } static av_cold void uninit(AVFilterContext *ctx) { FPSContext *s = ctx->priv; if (s->fifo) { s->drop += av_fifo_size(s->fifo) / sizeof(AVFilterBufferRef*); flush_fifo(s->fifo); av_fifo_free(s->fifo); } av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, " "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup); } static int config_props(AVFilterLink* link) { FPSContext *s = link->src->priv; link->time_base = (AVRational){ s->framerate.den, s->framerate.num }; link->w = link->src->inputs[0]->w; link->h = link->src->inputs[0]->h; return 0; } static int request_frame(AVFilterLink *outlink) { AVFilterContext *ctx = outlink->src; FPSContext *s = ctx->priv; int frames_out = s->frames_out; int ret = 0; while (ret >= 0 && s->frames_out == frames_out) ret = ff_request_frame(ctx->inputs[0]); /* flush the fifo */ if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) { int i; for (i = 0; av_fifo_size(s->fifo); i++) { AVFrame *buf; av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL); buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base, outlink->time_base) + s->frames_out; if ((ret = ff_filter_frame(outlink, buf)) < 0) return ret; s->frames_out++; } return 0; } return ret; } static int write_to_fifo(AVFifoBuffer *fifo, AVFrame *buf) { int ret; if (!av_fifo_space(fifo) && (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) { av_frame_free(&buf); return ret; } av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL); return 0; } static int filter_frame(AVFilterLink *inlink, AVFrame *buf) { AVFilterContext *ctx = inlink->dst; FPSContext *s = ctx->priv; AVFilterLink *outlink = ctx->outputs[0]; int64_t delta; int i, ret; s->frames_in++; /* discard frames until we get the first timestamp */ if (s->pts == AV_NOPTS_VALUE) { if (buf->pts != AV_NOPTS_VALUE) { ret = write_to_fifo(s->fifo, buf); if (ret < 0) return ret; if (s->start_time != DBL_MAX) { double first_pts = s->start_time * AV_TIME_BASE; first_pts = FFMIN(FFMAX(first_pts, INT64_MIN), INT64_MAX); s->first_pts = s->pts = av_rescale_q(first_pts, AV_TIME_BASE_Q, inlink->time_base); av_log(ctx, AV_LOG_VERBOSE, "Set first pts to (in:%"PRId64" out:%"PRId64")\n", s->first_pts, av_rescale_q(first_pts, AV_TIME_BASE_Q, outlink->time_base)); } else { s->first_pts = s->pts = buf->pts; } } else { av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no " "timestamp.\n"); av_frame_free(&buf); s->drop++; } return 0; } /* now wait for the next timestamp */ if (buf->pts == AV_NOPTS_VALUE) { return write_to_fifo(s->fifo, buf); } /* number of output frames */ delta = av_rescale_q(buf->pts - s->pts, inlink->time_base, outlink->time_base); if (delta < 1) { /* drop the frame and everything buffered except the first */ AVFrame *tmp; int drop = av_fifo_size(s->fifo)/sizeof(AVFrame*); av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop); s->drop += drop; av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL); flush_fifo(s->fifo); ret = write_to_fifo(s->fifo, tmp); av_frame_free(&buf); return ret; } /* can output >= 1 frames */ for (i = 0; i < delta; i++) { AVFrame *buf_out; av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL); /* duplicate the frame if needed */ if (!av_fifo_size(s->fifo) && i < delta - 1) { AVFrame *dup = av_frame_clone(buf_out); av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n"); if (dup) ret = write_to_fifo(s->fifo, dup); else ret = AVERROR(ENOMEM); if (ret < 0) { av_frame_free(&buf_out); av_frame_free(&buf); return ret; } s->dup++; } buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base, outlink->time_base) + s->frames_out; if ((ret = ff_filter_frame(outlink, buf_out)) < 0) { av_frame_free(&buf); return ret; } s->frames_out++; } flush_fifo(s->fifo); ret = write_to_fifo(s->fifo, buf); s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base); return ret; } static const AVFilterPad avfilter_vf_fps_inputs[] = { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, .filter_frame = filter_frame, }, { NULL } }; static const AVFilterPad avfilter_vf_fps_outputs[] = { { .name = "default", .type = AVMEDIA_TYPE_VIDEO, .request_frame = request_frame, .config_props = config_props }, { NULL } }; AVFilter ff_vf_fps = { .name = "fps", .description = NULL_IF_CONFIG_SMALL("Force constant framerate"), .init = init, .uninit = uninit, .priv_size = sizeof(FPSContext), .priv_class = &class, .inputs = avfilter_vf_fps_inputs, .outputs = avfilter_vf_fps_outputs, };