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Diffstat (limited to 'src/advtime.c')
| -rw-r--r-- | src/advtime.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/src/advtime.c b/src/advtime.c new file mode 100644 index 0000000..a13aaa6 --- /dev/null +++ b/src/advtime.c @@ -0,0 +1,182 @@ +/** + * @file + * libavcodec API use example. + * + * @example libavcodec/api-example.c + * Note that this library only handles codecs (mpeg, mpeg4, etc...), + * not file formats (avi, vob, etc...). See library 'libavformat' for the + * format handling + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#ifdef HAVE_AV_CONFIG_H +#undef HAVE_AV_CONFIG_H +#endif + +#include <libavcodec/avcodec.h> +#include <libavutil/audioconvert.h> +#include <libavutil/common.h> +#include <libavutil/imgutils.h> +#include <libavutil/mathematics.h> +#include <libavutil/samplefmt.h> + +#define INBUF_SIZE 4096 +#define AUDIO_INBUF_SIZE 20480 +#define AUDIO_REFILL_THRESH 4096 + +/* + * Video decoding example + */ + +static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize, + char *filename) +{ + FILE *f; + int i; + + f=fopen(filename,"w"); + fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255); + for(i=0;i<ysize;i++) + fwrite(buf + i * wrap,1,xsize,f); + fclose(f); +} + +static void video_decode_example(const char *outfilename, const char *filename) +{ + AVCodec *codec; + AVCodecContext *c= NULL; + int frame, got_picture, len; + FILE *f; + AVFrame *picture; + uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE]; + char buf[1024]; + AVPacket avpkt; + + av_init_packet(&avpkt); + + /* set end of buffer to 0 (this ensures that no overreading happens for damaged mpeg streams) */ + memset(inbuf + INBUF_SIZE, 0, FF_INPUT_BUFFER_PADDING_SIZE); + + printf("Video decoding\n"); + + /* find the mpeg1 video decoder */ + codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO); + if (!codec) { + fprintf(stderr, "codec not found\n"); + exit(1); + } + + c = avcodec_alloc_context3(codec); + picture= avcodec_alloc_frame(); + + if(codec->capabilities&CODEC_CAP_TRUNCATED) + c->flags|= CODEC_FLAG_TRUNCATED; /* we do not send complete frames */ + + /* For some codecs, such as msmpeg4 and mpeg4, width and height + MUST be initialized there because this information is not + available in the bitstream. */ + + /* open it */ + if (avcodec_open2(c, codec, NULL) < 0) { + fprintf(stderr, "could not open codec\n"); + exit(1); + } + + /* the codec gives us the frame size, in samples */ + + f = fopen(filename, "rb"); + if (!f) { + fprintf(stderr, "could not open %s\n", filename); + exit(1); + } + + frame = 0; + for(;;) { + avpkt.size = fread(inbuf, 1, INBUF_SIZE, f); + if (avpkt.size == 0) + break; + + /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio) + and this is the only method to use them because you cannot + know the compressed data size before analysing it. + + BUT some other codecs (msmpeg4, mpeg4) are inherently frame + based, so you must call them with all the data for one + frame exactly. You must also initialize 'width' and + 'height' before initializing them. */ + + /* NOTE2: some codecs allow the raw parameters (frame size, + sample rate) to be changed at any frame. We handle this, so + you should also take care of it */ + + /* here, we use a stream based decoder (mpeg1video), so we + feed decoder and see if it could decode a frame */ + avpkt.data = inbuf; + while (avpkt.size > 0) { + len = avcodec_decode_video2(c, picture, &got_picture, &avpkt); + if (len < 0) { + fprintf(stderr, "Error while decoding frame %d\n", frame); + exit(1); + } + if (got_picture) { + printf("saving frame %3d\n", frame); + fflush(stdout); + + /* the picture is allocated by the decoder. no need to + free it */ + snprintf(buf, sizeof(buf), outfilename, frame); + pgm_save(picture->data[0], picture->linesize[0], + c->width, c->height, buf); + frame++; + } + avpkt.size -= len; + avpkt.data += len; + } + } + + /* some codecs, such as MPEG, transmit the I and P frame with a + latency of one frame. You must do the following to have a + chance to get the last frame of the video */ + avpkt.data = NULL; + avpkt.size = 0; + len = avcodec_decode_video2(c, picture, &got_picture, &avpkt); + if (got_picture) { + printf("saving last frame %3d\n", frame); + fflush(stdout); + + /* the picture is allocated by the decoder. no need to + free it */ + snprintf(buf, sizeof(buf), outfilename, frame); + pgm_save(picture->data[0], picture->linesize[0], + c->width, c->height, buf); + frame++; + } + + fclose(f); + + avcodec_close(c); + av_free(c); + avcodec_free_frame(&picture); + printf("\n"); +} + +int main(int argc, char **argv) +{ + if (argc < 2) + return 1; + + /* register all the codecs */ + avcodec_register_all(); + +// FILE *fh = fopen(argv[1], "rb"); +// if (fh == NULL) +// return 1; + + video_decode_example(argv[1], filename); + +// fclose(sh); + return 0; +} |