From c8ef309379709062391f5e012efc3609a3389917 Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Wed, 29 Aug 2012 23:41:30 +0200 Subject: examples: add demuxing.c example --- doc/examples/Makefile | 1 + doc/examples/demuxing.c | 193 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 194 insertions(+) create mode 100644 doc/examples/demuxing.c (limited to 'doc') diff --git a/doc/examples/Makefile b/doc/examples/Makefile index 287dfc4..e8aab57 100644 --- a/doc/examples/Makefile +++ b/doc/examples/Makefile @@ -12,6 +12,7 @@ CFLAGS := $(shell pkg-config --cflags $(FFMPEG_LIBS)) $(CFLAGS) LDLIBS := $(shell pkg-config --libs $(FFMPEG_LIBS)) $(LDLIBS) EXAMPLES= decoding_encoding \ + demuxing \ filtering_video \ filtering_audio \ metadata \ diff --git a/doc/examples/demuxing.c b/doc/examples/demuxing.c new file mode 100644 index 0000000..fca7feb --- /dev/null +++ b/doc/examples/demuxing.c @@ -0,0 +1,193 @@ +/* + * Copyright (c) 2012 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 + * libavformat demuxing API use example. + * + * Show how to use the libavformat and libavcodec API to demux and + * decode video data. + */ + +#include +#include +#include + +static AVFormatContext *fmt_ctx = NULL; +static AVCodecContext *dec_ctx = NULL; +static AVCodec *dec = NULL; +static AVStream *stream = NULL; +static const char *src_filename = NULL; +static const char *dst_filename = NULL; +static FILE *dst_file = NULL; +static uint8_t *dst_data[4] = {NULL}; +static int dst_linesize[4]; +static int dst_bufsize; +static int stream_idx; +static AVFrame *frame = NULL; +static AVPacket pkt; +static int frame_count = 0; + +static int decode_packet(int *got_frame, int cached) +{ + int ret; + + if (pkt.stream_index != stream_idx) + return 0; + + /* decode video frame */ + ret = avcodec_decode_video2(dec_ctx, frame, got_frame, &pkt); + if (ret < 0) { + fprintf(stderr, "Error decoding video frame\n"); + return ret; + } + + if (*got_frame) { + printf("frame%s n:%d coded_n:%d pts:%s\n", + cached ? "(cached)" : "", + frame_count++, frame->coded_picture_number, + av_ts2timestr(frame->pts, &dec_ctx->time_base)); + + /* copy decoded frame to destination buffer: + * this is required since rawvideo expect non aligned data */ + av_image_copy(dst_data, dst_linesize, + (const uint8_t **)(frame->data), frame->linesize, + dec_ctx->pix_fmt, dec_ctx->width, dec_ctx->height); + + /* write to rawvideo file */ + fwrite(dst_data[0], 1, dst_bufsize, dst_file); + } + + return ret; +} + +int main (int argc, char **argv) +{ + int ret, got_frame; + + if (argc != 3) { + fprintf(stderr, "usage: %s input_file output_file\n" + "API example program to show how to read frames from an input file.\n" + "This program reads frames from a file, decode them, and write them " + "to a rawvideo file named like output_file." + "\n", argv[0]); + exit(1); + } + src_filename = argv[1]; + dst_filename = argv[2]; + + /* register all formats and codecs */ + av_register_all(); + + /* open input file, and allocated format context */ + if (avformat_open_input(&fmt_ctx, src_filename, NULL, NULL) < 0) { + fprintf(stderr, "Could not open source file %s\n", src_filename); + exit(1); + } + + /* retrieve stream information */ + if (avformat_find_stream_info(fmt_ctx, NULL) < 0) { + fprintf(stderr, "Could not find stream information\n"); + exit(1); + } + + ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0); + if (ret < 0) { + fprintf(stderr, "Could not find video stream in file\n"); + goto end; + } + stream_idx = ret; + stream = fmt_ctx->streams[stream_idx]; + + /* find decoder for the stream */ + dec_ctx = stream->codec; + dec = avcodec_find_decoder(dec_ctx->codec_id); + if (!dec) { + fprintf(stderr, "Failed to find any codec\n"); + ret = 1; + goto end; + } + + if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) { + fprintf(stderr, "Failed to open codec\n"); + goto end; + } + + /* dump input information to stderr */ + av_dump_format(fmt_ctx, 0, src_filename, 0); + + dst_file = fopen(dst_filename, "wb"); + if (!dst_file) { + fprintf(stderr, "Could not open destination file %s\n", dst_filename); + ret = 1; + goto end; + } + + frame = avcodec_alloc_frame(); + if (!frame) { + fprintf(stderr, "Could not allocate video frame\n"); + ret = 1; + goto end; + } + + /* allocate image where the decoded image will be put */ + ret = av_image_alloc(dst_data, dst_linesize, + dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt, 1); + if (ret < 0) { + fprintf(stderr, "Could not alloc raw video buffer\n"); + goto end; + } + dst_bufsize = ret; + + /* initialize packet, set data to NULL, let the demuxer fill it */ + av_init_packet(&pkt); + pkt.size = 0; + pkt.data = NULL; + + printf("Demuxing file '%s' to '%s'\n", src_filename, dst_filename); + + /* read frames from the file */ + while (av_read_frame(fmt_ctx, &pkt) >= 0) + decode_packet(&got_frame, 0); + + /* flush cached frames */ + pkt.data = NULL; + pkt.size = 0; + do { + decode_packet(&got_frame, 1); + } while (got_frame); + + printf("Demuxing succeeded. Play the output file with the command:\n" + "ffplay -f rawvideo -pix_fmt %s -video_size %dx%d %s\n", + av_get_pix_fmt_name(dec_ctx->pix_fmt), dec_ctx->width, dec_ctx->height, + dst_filename); + +end: + avcodec_close(dec_ctx); + avformat_close_input(&fmt_ctx); + if (dst_file) + fclose(dst_file); + av_free(frame); + av_free(dst_data[0]); + + return ret < 0; +} -- cgit v1.1