id,summary,reporter,owner,description,type,status,priority,component,version,resolution,keywords,cc,blockedby,blocking,reproduced,analyzed
1981,mpegtsraw open of multicast stream may hang,Krieger,,"Summary of the bug:
When opening many multicast UDP streams using avformat_open_input(), some instances may loop infinitely in mpegts_read_header() in lines 2016-2030.
Inspecting with gdb shows that nb_packets number is big, so it does not hang inside avio-stuff.
How to reproduce:
{{{
1. Have a lot of multicast MPEGTS streams. I had my on udp://239.195.0.1-50:1234
2. Code snippet:

#include <assert.h>
#include <stdio.h>
#include <pthread.h>
#include <libavformat/avformat.h>

#define THREADS_NUM 50

void *thread_work(void* dummy) {
  int ret;
  int i;
  char *url = dummy;
  printf(""'%s' thread starts\n"", url);
  AVFormatContext *ctx = avformat_alloc_context();
  assert(ctx);
  AVDictionary *avio_opts = NULL;
  av_dict_set(&avio_opts, ""timeout"", ""2000000"", 0);
  av_dict_set(&avio_opts, ""fifo_size"", ""0"", 0);  // bug happens both with and without separate UDP-fetching thread
  ret = avio_open2(&ctx->pb, url, AVIO_FLAG_READ, NULL, &avio_opts);
  assert(!ret);
  ret = avformat_open_input(&ctx, url, av_find_input_format(""mpegtsraw""), NULL);
  if (!ret) {
    // read a bit, to add networking load
    for (i = 0; i < 1000; i++) {
      AVPacket pkt;
      ret = av_read_frame(ctx, &pkt);
    }
  }
  printf(""'%s' thread exits\n"", url);
  return NULL;
}

int main() {
  int ret;
  int i;
  pthread_t tids[THREADS_NUM];

  av_register_all();
  avformat_network_init();

  for (i = 0; i < THREADS_NUM; i++) {
    char *url = NULL;
    ret = asprintf(&url, ""udp://239.195.0.%d:1234"", i+1);
    assert(ret != -1);
    ret = pthread_create(&tids[i], NULL, thread_work, url);
    printf(""created %d-th thread\n"", i);
    assert(!ret);
  }
  for (i = 0; i < THREADS_NUM; i++) {
    pthread_join(tids[i], NULL);
    printf(""joined %d-th thread\n"", i);
  }
  return 0;
}

The defective result is that the application does not terminate. This happens not in 100% of launch cases, but happens most of times.
I could not replicate this bug on local UDP streams, sorry.
The same problem affects libav.org fork.
}}}",defect,closed,normal,avformat,git-master,needs_more_info,mpegtsraw,,,,0,0