mirror of https://git.ffmpeg.org/ffmpeg.git
294 lines
9.5 KiB
C
294 lines
9.5 KiB
C
/*
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* Copyright (c) 2010 Nicolas George
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* Copyright (c) 2011 Stefano Sabatini
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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/**
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* @file
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* API example for decoding and filtering
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* @example filtering_video.c
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*/
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#define _XOPEN_SOURCE 600 /* for usleep */
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#include <unistd.h>
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#include <libavcodec/avcodec.h>
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#include <libavformat/avformat.h>
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#include <libavfilter/avfiltergraph.h>
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#include <libavfilter/buffersink.h>
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#include <libavfilter/buffersrc.h>
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#include <libavutil/opt.h>
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const char *filter_descr = "scale=78:24,transpose=cclock";
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/* other way:
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scale=78:24 [scl]; [scl] transpose=cclock // assumes "[in]" and "[out]" to be input output pads respectively
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*/
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static AVFormatContext *fmt_ctx;
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static AVCodecContext *dec_ctx;
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AVFilterContext *buffersink_ctx;
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AVFilterContext *buffersrc_ctx;
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AVFilterGraph *filter_graph;
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static int video_stream_index = -1;
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static int64_t last_pts = AV_NOPTS_VALUE;
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static int open_input_file(const char *filename)
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{
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int ret;
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AVCodec *dec;
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if ((ret = avformat_open_input(&fmt_ctx, filename, NULL, NULL)) < 0) {
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av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");
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return ret;
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}
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if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) < 0) {
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av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");
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return ret;
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}
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/* select the video stream */
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ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &dec, 0);
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if (ret < 0) {
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av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file\n");
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return ret;
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}
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video_stream_index = ret;
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/* create decoding context */
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dec_ctx = avcodec_alloc_context3(dec);
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if (!dec_ctx)
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return AVERROR(ENOMEM);
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avcodec_parameters_to_context(dec_ctx, fmt_ctx->streams[video_stream_index]->codecpar);
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av_opt_set_int(dec_ctx, "refcounted_frames", 1, 0);
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/* init the video decoder */
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if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) {
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av_log(NULL, AV_LOG_ERROR, "Cannot open video decoder\n");
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return ret;
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}
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return 0;
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}
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static int init_filters(const char *filters_descr)
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{
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char args[512];
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int ret = 0;
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AVFilter *buffersrc = avfilter_get_by_name("buffer");
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AVFilter *buffersink = avfilter_get_by_name("buffersink");
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AVFilterInOut *outputs = avfilter_inout_alloc();
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AVFilterInOut *inputs = avfilter_inout_alloc();
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AVRational time_base = fmt_ctx->streams[video_stream_index]->time_base;
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enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE };
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filter_graph = avfilter_graph_alloc();
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if (!outputs || !inputs || !filter_graph) {
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ret = AVERROR(ENOMEM);
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goto end;
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}
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/* buffer video source: the decoded frames from the decoder will be inserted here. */
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snprintf(args, sizeof(args),
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"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
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dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,
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time_base.num, time_base.den,
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dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
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ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",
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args, NULL, filter_graph);
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if (ret < 0) {
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av_log(NULL, AV_LOG_ERROR, "Cannot create buffer source\n");
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goto end;
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}
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/* buffer video sink: to terminate the filter chain. */
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ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",
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NULL, NULL, filter_graph);
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if (ret < 0) {
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av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n");
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goto end;
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}
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ret = av_opt_set_int_list(buffersink_ctx, "pix_fmts", pix_fmts,
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AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN);
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if (ret < 0) {
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av_log(NULL, AV_LOG_ERROR, "Cannot set output pixel format\n");
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goto end;
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}
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/*
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* Set the endpoints for the filter graph. The filter_graph will
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* be linked to the graph described by filters_descr.
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*/
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/*
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* The buffer source output must be connected to the input pad of
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* the first filter described by filters_descr; since the first
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* filter input label is not specified, it is set to "in" by
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* default.
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*/
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outputs->name = av_strdup("in");
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outputs->filter_ctx = buffersrc_ctx;
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outputs->pad_idx = 0;
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outputs->next = NULL;
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/*
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* The buffer sink input must be connected to the output pad of
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* the last filter described by filters_descr; since the last
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* filter output label is not specified, it is set to "out" by
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* default.
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*/
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inputs->name = av_strdup("out");
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inputs->filter_ctx = buffersink_ctx;
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inputs->pad_idx = 0;
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inputs->next = NULL;
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if ((ret = avfilter_graph_parse_ptr(filter_graph, filters_descr,
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&inputs, &outputs, NULL)) < 0)
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goto end;
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if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0)
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goto end;
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end:
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avfilter_inout_free(&inputs);
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avfilter_inout_free(&outputs);
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return ret;
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}
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static void display_frame(const AVFrame *frame, AVRational time_base)
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{
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int x, y;
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uint8_t *p0, *p;
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int64_t delay;
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if (frame->pts != AV_NOPTS_VALUE) {
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if (last_pts != AV_NOPTS_VALUE) {
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/* sleep roughly the right amount of time;
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* usleep is in microseconds, just like AV_TIME_BASE. */
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delay = av_rescale_q(frame->pts - last_pts,
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time_base, AV_TIME_BASE_Q);
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if (delay > 0 && delay < 1000000)
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usleep(delay);
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}
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last_pts = frame->pts;
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}
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/* Trivial ASCII grayscale display. */
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p0 = frame->data[0];
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puts("\033c");
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for (y = 0; y < frame->height; y++) {
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p = p0;
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for (x = 0; x < frame->width; x++)
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putchar(" .-+#"[*(p++) / 52]);
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putchar('\n');
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p0 += frame->linesize[0];
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}
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fflush(stdout);
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}
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int main(int argc, char **argv)
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{
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int ret;
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AVPacket packet;
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AVFrame *frame = av_frame_alloc();
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AVFrame *filt_frame = av_frame_alloc();
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if (!frame || !filt_frame) {
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perror("Could not allocate frame");
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exit(1);
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}
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if (argc != 2) {
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fprintf(stderr, "Usage: %s file\n", argv[0]);
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exit(1);
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}
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av_register_all();
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avfilter_register_all();
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if ((ret = open_input_file(argv[1])) < 0)
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goto end;
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if ((ret = init_filters(filter_descr)) < 0)
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goto end;
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/* read all packets */
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while (1) {
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if ((ret = av_read_frame(fmt_ctx, &packet)) < 0)
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break;
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if (packet.stream_index == video_stream_index) {
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ret = avcodec_send_packet(dec_ctx, &packet);
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if (ret < 0) {
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av_log(NULL, AV_LOG_ERROR, "Error while sending a packet to the decoder\n");
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break;
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}
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while (ret >= 0) {
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ret = avcodec_receive_frame(dec_ctx, frame);
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if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
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break;
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} else if (ret < 0) {
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av_log(NULL, AV_LOG_ERROR, "Error while receiving a frame from the decoder\n");
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goto end;
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}
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if (ret >= 0) {
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frame->pts = av_frame_get_best_effort_timestamp(frame);
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/* push the decoded frame into the filtergraph */
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if (av_buffersrc_add_frame_flags(buffersrc_ctx, frame, AV_BUFFERSRC_FLAG_KEEP_REF) < 0) {
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av_log(NULL, AV_LOG_ERROR, "Error while feeding the filtergraph\n");
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break;
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}
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/* pull filtered frames from the filtergraph */
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while (1) {
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ret = av_buffersink_get_frame(buffersink_ctx, filt_frame);
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if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
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break;
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if (ret < 0)
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goto end;
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display_frame(filt_frame, buffersink_ctx->inputs[0]->time_base);
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av_frame_unref(filt_frame);
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}
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av_frame_unref(frame);
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}
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}
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}
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av_packet_unref(&packet);
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}
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end:
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avfilter_graph_free(&filter_graph);
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avcodec_free_context(&dec_ctx);
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avformat_close_input(&fmt_ctx);
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av_frame_free(&frame);
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av_frame_free(&filt_frame);
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if (ret < 0 && ret != AVERROR_EOF) {
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fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
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exit(1);
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}
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exit(0);
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}
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