From fcc7d869d98838356e3e778afe2196a12bfcd2b1 Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Tue, 21 Jun 2011 00:33:37 +0200 Subject: doc/examples: add decoding/filtering example program --- doc/examples/Makefile | 2 +- doc/examples/filtering.c | 230 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 231 insertions(+), 1 deletion(-) create mode 100644 doc/examples/filtering.c diff --git a/doc/examples/Makefile b/doc/examples/Makefile index f8abdff4e3..fde2256fca 100644 --- a/doc/examples/Makefile +++ b/doc/examples/Makefile @@ -3,7 +3,7 @@ FFMPEG_LIBS=libavdevice libavformat libavfilter libavcodec libswscale libavutil CFLAGS+=$(shell pkg-config --cflags $(FFMPEG_LIBS)) LDFLAGS+=$(shell pkg-config --libs $(FFMPEG_LIBS)) -EXAMPLES=encoding metadata muxing +EXAMPLES=encoding filtering metadata muxing OBJS=$(addsuffix .o,$(EXAMPLES)) diff --git a/doc/examples/filtering.c b/doc/examples/filtering.c new file mode 100644 index 0000000000..369cc03e80 --- /dev/null +++ b/doc/examples/filtering.c @@ -0,0 +1,230 @@ +/* + * Copyright (c) 2010 Nicolas George + * Copyright (c) 2011 Stefano Sabatini + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +/** + * @file + * API example for decoding and filtering + */ + +#define _XOPEN_SOURCE 600 /* for usleep */ + +#include +#include +#include +#include +#include + +const char *filter_descr = "scale=78:24"; + +static AVFormatContext *fmt_ctx; +static AVCodecContext *dec_ctx; +AVFilterContext *buffersink_ctx; +AVFilterContext *buffersrc_ctx; +AVFilterGraph *filter_graph; +static int video_stream_index = -1; +static int64_t last_pts = AV_NOPTS_VALUE; + +static int open_input_file(const char *filename) +{ + int ret, i; + AVCodec *dec; + + if ((ret = avformat_open_input(&fmt_ctx, filename, NULL, NULL)) < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n"); + return ret; + } + + if ((ret = av_find_stream_info(fmt_ctx)) < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n"); + return ret; + } + + /* select the video stream */ + ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &dec, 0); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file\n"); + return ret; + } + video_stream_index = ret; + dec_ctx = fmt_ctx->streams[video_stream_index]->codec; + + /* init the video decoder */ + if ((ret = avcodec_open(dec_ctx, dec)) < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot open video decoder\n"); + return ret; + } + + return 0; +} + +static int init_filters(const char *filters_descr) +{ + char args[512]; + int ret; + AVFilter *buffersrc = avfilter_get_by_name("buffer"); + AVFilter *buffersink = avfilter_get_by_name("buffersink"); + AVFilterInOut *outputs = avfilter_inout_alloc(); + AVFilterInOut *inputs = avfilter_inout_alloc(); + enum PixelFormat pix_fmts[] = { PIX_FMT_GRAY8, PIX_FMT_NONE }; + filter_graph = avfilter_graph_alloc(); + + /* buffer video source: the decoded frames from the decoder will be inserted here. */ + snprintf(args, sizeof(args), "%d:%d:%d:%d:%d:%d:%d", + dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt, + dec_ctx->time_base.num, dec_ctx->time_base.den, + dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den); + ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in", + args, NULL, filter_graph); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot create buffer source\n"); + return ret; + } + + /* buffer video sink: to terminate the filter chain. */ + ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out", + NULL, pix_fmts, filter_graph); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n"); + return ret; + } + + /* Endpoints for the filter graph. */ + outputs->name = av_strdup("in"); + outputs->filter_ctx = buffersrc_ctx; + outputs->pad_idx = 0; + outputs->next = NULL; + + inputs->name = av_strdup("out"); + inputs->filter_ctx = buffersink_ctx; + inputs->pad_idx = 0; + inputs->next = NULL; + + if ((ret = avfilter_graph_parse(filter_graph, filter_descr, + &inputs, &outputs, NULL)) < 0) + return ret; + + if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0) + return ret; +} + +static void display_picref(AVFilterBufferRef *picref, AVRational time_base) +{ + int x, y; + uint8_t *p0, *p; + int64_t delay; + + if (picref->pts != AV_NOPTS_VALUE) { + if (last_pts != AV_NOPTS_VALUE) { + /* sleep roughly the right amount of time; + * usleep is in microseconds, just like AV_TIME_BASE. */ + delay = av_rescale_q(picref->pts - last_pts, + time_base, AV_TIME_BASE_Q); + if (delay > 0 && delay < 1000000) + usleep(delay); + } + last_pts = picref->pts; + } + + /* Trivial ASCII grayscale display. */ + p0 = picref->data[0]; + puts("\033c"); + for (y = 0; y < picref->video->h; y++) { + p = p0; + for (x = 0; x < picref->video->w; x++) + putchar(" .-+#"[*(p++) / 52]); + putchar('\n'); + p0 += picref->linesize[0]; + } + fflush(stdout); +} + +int main(int argc, char **argv) +{ + int ret; + AVPacket packet; + AVFrame frame; + int got_frame; + + if (argc != 2) { + fprintf(stderr, "Usage: %s file\n", argv[0]); + exit(1); + } + + avcodec_register_all(); + av_register_all(); + avfilter_register_all(); + + if ((ret = open_input_file(argv[1]) < 0)) + goto end; + if ((ret = init_filters(filter_descr)) < 0) + goto end; + + /* read all packets */ + while (1) { + AVFilterBufferRef *picref; + if ((ret = av_read_frame(fmt_ctx, &packet)) < 0) + break; + + if (packet.stream_index == video_stream_index) { + avcodec_get_frame_defaults(&frame); + got_frame = 0; + ret = avcodec_decode_video2(dec_ctx, &frame, &got_frame, &packet); + av_free_packet(&packet); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Error decoding video\n"); + break; + } + + if (got_frame) { + if (frame.pts == AV_NOPTS_VALUE) + frame.pts = frame.pkt_dts == AV_NOPTS_VALUE ? + frame.pkt_dts : frame.pkt_pts; + /* push the decoded frame into the filtergraph */ + av_vsrc_buffer_add_frame(buffersrc_ctx, &frame); + + /* pull filtered pictures from the filtergraph */ + while (avfilter_poll_frame(buffersink_ctx->inputs[0])) { + av_vsink_buffer_get_video_buffer_ref(buffersink_ctx, &picref, 0); + if (picref) { + display_picref(picref, buffersink_ctx->inputs[0]->time_base); + avfilter_unref_buffer(picref); + } + } + } + } + } +end: + avfilter_graph_free(&filter_graph); + if (dec_ctx) + avcodec_close(dec_ctx); + av_close_input_file(fmt_ctx); + + if (ret < 0 && ret != AVERROR_EOF) { + char buf[1024]; + av_strerror(ret, buf, sizeof(buf)); + fprintf(stderr, "Error occurred: %s\n", buf); + exit(1); + } + + exit(0); +} -- cgit v1.2.3