changing number of channels/sample rate midstream

[Elon Musk]

Midstream changing number of channels or sample rate causes SEGV.

Should be reproducible with any container/codec that support midstream change of such parameters.

> ./ffmpeg_g -err_detect 0 -i /tmp/crash2.tak -f null -
ffmpeg version git-2012-10-07-9fc53f2 Copyright (c) 2000-2012 the FFmpeg developers
  built on Oct  7 2012 18:00:27 with FreeBSD clang version 3.1 (branches/release_31 156863) 20120523
  configuration: --disable-everything --cc=clang --enable-decoder='dca,tak,ape,flac,pcm_s16le,pcm_s16be,pcm_s8,pcm_u8,pcm_s24le,pcm_s24be,pcm_s32le,pcm_s32be,pcm_f32le,pcm_f32be,pcm_f64le,pcm_f64be' --enable-enco
der='flac,pcm_s16le,pcm_s16be,pcm_s8,pcm_u8,pcm_s24le,pcm_s24be,pcm_s32le,pcm_s32be,pcm_f64le,pcm_f64be' --enable-protocol='file,pipe' --enable-demuxer='dts,dtshd,tak,wav,flac,ape' --enable-muxer='wav,flac,null,framemd5,md5,crc,framecrc' --enable-filter='aresample,anull,abuffer,aconvert,afifo,aformat,ashowinfo,anullsink,abuffersink,asetnsamples' --enable-bzlib --enable-zlib
  libavutil      51. 73.102 / 51. 73.102
  libavcodec     54. 65.100 / 54. 65.100
  libavformat    54. 30.100 / 54. 30.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 19.102 /  3. 19.102
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 16.100 /  0. 16.100
[tak @ 0x28819100] max_analyze_duration 5000000 reached at 5000000
Guessed Channel Layout for  Input Stream #0.0 : 4.0
Input #0, tak, from '/tmp/crash2.tak':
  Duration: 00:01:00.48, start: 0.000000, bitrate: 861 kb/s
    Stream #0:0: Audio: tak, 44100 Hz, 4.0, s16p
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf54.30.100
    Stream #0:0: Audio: pcm_s16le, 44100 Hz, 4.0, s16, 2822 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (tak -> pcm_s16le)
Press [q] to stop, [?] for help
Error while decoding stream #0:0: Invalid data found when processing input
    Last message repeated 36 times
Input stream #0:0 frame changed from rate:44100 fmt:s16p ch:4 chl:4.0 to rate:44100 fmt:s16p ch:2 chl:2 channels (FL+FR+FC+BC)
Segmentation fault (core dumped)
> gdb ffmpeg_g ffmpeg_g.core 
GNU gdb 6.1.1 [FreeBSD]
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This GDB was configured as "i386-marcel-freebsd"...
Core was generated by `ffmpeg_g'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /lib/libm.so.5...done.
Loaded symbols for /lib/libm.so.5
Reading symbols from /lib/libz.so.6...done.
Loaded symbols for /lib/libz.so.6
Reading symbols from /lib/libthr.so.3...done.
Loaded symbols for /lib/libthr.so.3
Reading symbols from /lib/libc.so.7...done.
Loaded symbols for /lib/libc.so.7
Reading symbols from /libexec/ld-elf.so.1...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x28370dae in memcpy () from /lib/libc.so.7
[New Thread 28803080 (LWP 100173/ffmpeg_g)]
(gdb) bt
#0  0x28370dae in memcpy () from /lib/libc.so.7
#1  0x081a1064 in av_samples_copy (dst=dwarf expression stack underflow
) at libavutil/samplefmt.c:217
#2  0x0806520a in ff_copy_buffer_ref (outlink=DWARF-2 expression error: DW_OP_reg operations must be used either alone or in conjuction with DW_OP_piece.
) at libavfilter/buffer.c:226
#3  0x08065802 in av_buffersrc_add_ref (s=dwarf2_read_address: Corrupted DWARF expression.
) at libavfilter/buffersrc.c:133
#4  0x080656ac in av_buffersrc_add_frame (buffer_src=dwarf2_read_address: Corrupted DWARF expression.
) at libavfilter/buffersrc.c:91
#5  0x0805b26f in output_packet (ist=Unhandled dwarf expression opcode 0xed
) at ffmpeg.c:1544
#6  0x08057252 in transcode () at ffmpeg.c:2839
#7  0x0805337c in main (argc=dwarf2_read_address: Corrupted DWARF expression.
) at ffmpeg.c:3171
(gdb) 

[Carl Eugen Hoyos]

Channel number changes work fine with the samples from ticket #200 and a random ac-3 sample here.

I am not sure if I ever tested a stream with sample rate change.

[Elon Musk]

This sample is different because it changes number of channels from 4 to 2 but channel layout remains same.

[Elon Musk]

Have been fixed in 02b238186a23d61859d9be8ca9356052f0216220.