mxf encoder segfaults on 1 frame input and mpeg2 long gop video

[Marton Balint]

Summary of the bug:

The mxf encoder segfaults when encoding 1 mpeg2 video with bframes from an 1 frame long source.

How to reproduce:

% ./ffmpeg -f lavfi -i "testsrc=d=0.01" -f lavfi -i "aevalsrc=1:d=0.01" -acodec pcm_s24le -ar 48000 -bf 2 -vcodec mpeg2video out.mxf
ffmpeg version N-74749-g648de46 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.8 (SUSE Linux)
  configuration: --disable-vaapi --enable-vdpau --enable-gpl --enable-libfreetype --enable-libzvbi --enable-libass --enable-frei0r --enable-openssl --enable-nonfree --enable-libx264 --enable-libfdk-aac --enable-nonfree
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 59.100 / 56. 59.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.100 /  5. 40.100
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
Input #0, lavfi, from 'testsrc=d=0.01':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 320x240 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
Input #1, lavfi, from 'aevalsrc=1:d=0.01':
  Duration: N/A, start: 0.000000, bitrate: 2822 kb/s
    Stream #1:0: Audio: pcm_f64le, 44100 Hz, mono, dbl, 2822 kb/s
File 'out.mxf' already exists. Overwrite ? [y/N] y
Output #0, mxf, to 'out.mxf':
  Metadata:
    encoder         : Lavf56.40.101
    Stream #0:0: Video: mpeg2video, yuv420p, 320x240 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
    Metadata:
      encoder         : Lavc56.59.100 mpeg2video
    Stream #0:1: Audio: pcm_s24le, 48000 Hz, mono, s32, 1152 kb/s
    Metadata:
      encoder         : Lavc56.59.100 pcm_s24le
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> mpeg2video (native))
  Stream #1:0 -> #0:1 (pcm_f64le (native) -> pcm_s24le (native))
Press [q] to stop, [?] for help
[mxf @ 0x3b16380] -d10_channelcount requires MXF D-10 and will be ignored
Segmentation fault

Valgrind output:

==16078== Invalid read of size 4
==16078==    at 0x61180F: mxf_write_packet (mxfenc.c:2451)
==16078==    by 0x602C1E: write_packet (mux.c:660)
==16078==    by 0x602C1E: av_write_trailer (mux.c:998)
==16078==    by 0x479859: transcode (ffmpeg.c:4016)
==16078==    by 0x479859: main (ffmpeg.c:4165)
==16078==  Address 0x180cc38860 is not stack'd, malloc'd or (recently) free'd

mxf->edit_units_count is zero therefore indexing with mxf->edit_units_count-1 will segfault...

[wim_arbor]

I have closed #4914 as a duplicate of this ticket. It crashes at the same location with the same condition.

[Carl Eugen Hoyos]

This crash was fixed by Alexis in 6e8d856ad6d3decfabad83bc169c2e7a16a16b55