early-access version 1432
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pineappleEA
187
externals/ffmpeg/doc/examples/decode_video.c
vendored
Executable file
187
externals/ffmpeg/doc/examples/decode_video.c
vendored
Executable file
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/*
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* Copyright (c) 2001 Fabrice Bellard
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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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* video decoding with libavcodec API example
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*
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* @example decode_video.c
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <libavcodec/avcodec.h>
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#define INBUF_SIZE 4096
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static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize,
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char *filename)
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{
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FILE *f;
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int i;
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f = fopen(filename,"w");
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fprintf(f, "P5\n%d %d\n%d\n", xsize, ysize, 255);
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for (i = 0; i < ysize; i++)
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fwrite(buf + i * wrap, 1, xsize, f);
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fclose(f);
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}
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static void decode(AVCodecContext *dec_ctx, AVFrame *frame, AVPacket *pkt,
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const char *filename)
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{
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char buf[1024];
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int ret;
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ret = avcodec_send_packet(dec_ctx, pkt);
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if (ret < 0) {
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fprintf(stderr, "Error sending a packet for decoding\n");
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exit(1);
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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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return;
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else if (ret < 0) {
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fprintf(stderr, "Error during decoding\n");
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exit(1);
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}
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printf("saving frame %3d\n", dec_ctx->frame_number);
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fflush(stdout);
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/* the picture is allocated by the decoder. no need to
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free it */
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snprintf(buf, sizeof(buf), "%s-%d", filename, dec_ctx->frame_number);
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pgm_save(frame->data[0], frame->linesize[0],
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frame->width, frame->height, buf);
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}
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}
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int main(int argc, char **argv)
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{
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const char *filename, *outfilename;
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const AVCodec *codec;
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AVCodecParserContext *parser;
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AVCodecContext *c= NULL;
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FILE *f;
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AVFrame *frame;
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uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
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uint8_t *data;
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size_t data_size;
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int ret;
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AVPacket *pkt;
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if (argc <= 2) {
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fprintf(stderr, "Usage: %s <input file> <output file>\n"
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"And check your input file is encoded by mpeg1video please.\n", argv[0]);
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exit(0);
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}
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filename = argv[1];
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outfilename = argv[2];
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pkt = av_packet_alloc();
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if (!pkt)
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exit(1);
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/* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */
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memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
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/* find the MPEG-1 video decoder */
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codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO);
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if (!codec) {
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fprintf(stderr, "Codec not found\n");
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exit(1);
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}
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parser = av_parser_init(codec->id);
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if (!parser) {
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fprintf(stderr, "parser not found\n");
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exit(1);
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}
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c = avcodec_alloc_context3(codec);
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if (!c) {
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fprintf(stderr, "Could not allocate video codec context\n");
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exit(1);
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}
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/* For some codecs, such as msmpeg4 and mpeg4, width and height
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MUST be initialized there because this information is not
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available in the bitstream. */
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/* open it */
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if (avcodec_open2(c, codec, NULL) < 0) {
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fprintf(stderr, "Could not open codec\n");
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exit(1);
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}
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f = fopen(filename, "rb");
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if (!f) {
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fprintf(stderr, "Could not open %s\n", filename);
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exit(1);
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}
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frame = av_frame_alloc();
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if (!frame) {
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fprintf(stderr, "Could not allocate video frame\n");
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exit(1);
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}
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while (!feof(f)) {
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/* read raw data from the input file */
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data_size = fread(inbuf, 1, INBUF_SIZE, f);
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if (!data_size)
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break;
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/* use the parser to split the data into frames */
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data = inbuf;
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while (data_size > 0) {
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ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size,
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data, data_size, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0);
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if (ret < 0) {
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fprintf(stderr, "Error while parsing\n");
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exit(1);
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}
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data += ret;
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data_size -= ret;
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if (pkt->size)
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decode(c, frame, pkt, outfilename);
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}
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}
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/* flush the decoder */
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decode(c, frame, NULL, outfilename);
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fclose(f);
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av_parser_close(parser);
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avcodec_free_context(&c);
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av_frame_free(&frame);
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av_packet_free(&pkt);
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return 0;
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}
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