Ticket #3124: ogg-seek.c

#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "libavutil/common.h"
#include "libavutil/mathematics.h"
#include "libavformat/avformat.h"

// Number of frames to print packet.pts information for.
static const int kFramesToPrint = 30;

int main(int argc, char *argv[]) {
  AVFormatContext *ctx = avformat_alloc_context();
  avformat_close_input(&ctx);

  if (argc < 2) {
    printf("usage: ./ogg-seek <audio file>\n");
    return -1;
  }
  av_log_set_level(AV_LOG_QUIET);

  av_register_all();
  AVFormatContext *format_context = NULL;
  if (avformat_open_input(&format_context, argv[1], NULL, NULL) != 0)
    return -1;

  if (avformat_find_stream_info(format_context, NULL) < 0)
    return -1;

  // Find first audio stream.
  int audio_stream_index = -1;
  for (int i = 0; i < format_context->nb_streams; i++) {
    if (format_context->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
      audio_stream_index = i;
      break;
    }
  }

  if (audio_stream_index == -1)
    return -1;

  // Read a few frames
  int frames = 0, ret = 0;
  AVPacket packet = { 0 };
  while ((ret = av_read_frame(format_context, &packet)) >= 0 && frames < 25) {
    if (packet.stream_index == audio_stream_index) {
      frames++;
      printf("pts: %05ld -- dts: %05ld\n", packet.pts, packet.dts);
    }
  }

  printf("--------------------\n");

  // Seek ahead of granule @ 96000.
  if (avformat_seek_file(format_context, 0, INT64_MIN, 88000, INT64_MAX, AVSEEK_FLAG_BACKWARD) < 0)
    return -1;

  // Read all frames, but only print kFramesToPrint.
  int64_t last_pts = -1000;
  while ((ret = av_read_frame(format_context, &packet)) >= 0) {
    if (packet.stream_index == audio_stream_index) {
      printf("pts: %05ld -- dts: %05ld", packet.pts, packet.dts);
      if (packet.pts < last_pts){
        printf(" <------------ BACKWARDS!\n");
        break;
      } else {
        last_pts = packet.pts;
        printf("\n");
      }
    }
  }

  avformat_close_input(&format_context);
  return 0;
}