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#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libavutil/avutil.h>
#include <libswscale/swscale.h>
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
ppm_save(unsigned char *buf, int wrap, int xsize, int ysize, char *filename)
{
FILE *f;
int i;
f = fopen(filename, "w");
fprintf(f,"P6\n%d %d\n%d\n", xsize, ysize, 255);
for(i=0; i < ysize; i++)
fwrite(buf + i * wrap, 3, xsize, f);
fclose(f);
}
int
main(int argc, char *argv[])
{
const char *filename = argv[1];
AVFormatContext *fmt_ctx = NULL;
int vid_stream = -1;
AVCodecContext *codec_ctx = NULL;
AVCodec *codec;
AVFrame *frame;
AVPacket packet;
int bytes_decoded, got_picture;
AVFrame *frame_rgb;
int nbytes;
uint8_t *buffer;
struct SwsContext *sws_ctx;
int timestamp = 0;
av_register_all();
#if DEBUG
av_log_set_level(AV_LOG_DEBUG);
printf("file: %s\n", filename);
#endif
if (argc < 2) {
fprintf(stderr, "usage: %s filename [timestamp]\n", argv[0]);
exit(1);
}
if (avformat_open_input(&fmt_ctx, filename, NULL, NULL) != 0)
exit(2);
if (avformat_find_stream_info(fmt_ctx, NULL) < 0)
exit(3);
#if DEBUG
av_dump_format(fmt_ctx, 0, filename, 0);
#endif
vid_stream = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO,
-1, -1, NULL, 0);
if (vid_stream == -1)
exit(4);
codec_ctx = fmt_ctx->streams[vid_stream]->codec;
timestamp = fmt_ctx->start_time==AV_NOPTS_VALUE ? 0:fmt_ctx->start_time;
#if 1
if (argc == 3 && atoi(argv[2]) > 0)
timestamp += atoi(argv[2]);
#endif
avformat_seek_file(fmt_ctx, -1, INT64_MIN, timestamp, INT64_MAX, 0);
codec = avcodec_find_decoder(codec_ctx->codec_id);
if (codec == NULL) {
fprintf(stderr, "Failed to find decoder!\n");
exit(5);
}
#if DEBUG
printf("has cap truncated: %d\n",
codec->capabilities & CODEC_CAP_TRUNCATED);
#endif
#if 0
if (codec->capabilities & CODEC_CAP_TRUNCATED)
codec_ctx->flags |= CODEC_FLAG_TRUNCATED;
#endif
if (avcodec_open2(codec_ctx, codec, NULL) < 0) {
fprintf(stderr, "Failed to open codec!\n");
exit(6);
}
packet.data = NULL;
do {
if (packet.data != NULL)
av_free_packet(&packet);
if (av_read_frame(fmt_ctx, &packet) < 0) {
fprintf(stderr, "Found no video stream packet!\n");
exit(30);
}
} while (packet.stream_index != vid_stream);
frame = avcodec_alloc_frame();
do {
#if DEBUG
printf("packet.data: %p, packet.size: %d, packet.stream_index: %d\n",
packet.data, packet.size, packet.stream_index);
#endif
bytes_decoded = avcodec_decode_video2(codec_ctx, frame,
&got_picture, &packet);
if (bytes_decoded < 0) {
fprintf(stderr, "Error while decoding frame!\n");
exit(12);
}
#if DEBUG
printf("bytes_decoded: %d, got_picture: %d\n",
bytes_decoded, got_picture);
#endif
} while (got_picture == 0 && packet.size > 0);
av_free_packet(&packet);
if (got_picture == 0)
exit(9);
pgm_save(frame->data[0], frame->linesize[0],
codec_ctx->width, codec_ctx->height, "foo.pgm");
#define CONVERT_TO_RGB 1
#if CONVERT_TO_RGB
frame_rgb = avcodec_alloc_frame();
if (!frame_rgb)
exit(9);
nbytes = avpicture_get_size(PIX_FMT_RGB24,
codec_ctx->width, codec_ctx->height);
buffer = calloc(nbytes, sizeof(uint8_t));
if (!buffer)
exit(10);
avpicture_fill((AVPicture *) frame_rgb, buffer, PIX_FMT_RGB24,
codec_ctx->width, codec_ctx->height);
sws_ctx = sws_getCachedContext(NULL,
codec_ctx->width, codec_ctx->height,
codec_ctx->pix_fmt,
codec_ctx->width, codec_ctx->height,
PIX_FMT_RGB24, SWS_BILINEAR,
NULL, NULL, NULL);
sws_scale(sws_ctx,
(const uint8_t *const *) frame->data, frame->linesize, 0,
codec_ctx->height, frame_rgb->data, frame_rgb->linesize);
ppm_save(frame_rgb->data[0], frame_rgb->linesize[0],
codec_ctx->width, codec_ctx->height, "foo.ppm");
#endif
free(buffer);
av_free(frame_rgb);
av_free(frame);
avcodec_close(codec_ctx);
#if LIBAVFORMAT_VERSION_INT >= AV_VERSION_INT(53, 17, 0)
avformat_close_input(&fmt_ctx);
#else
av_close_input_file(fmt_ctx);
#endif
return 0;
}
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