AR.Drone 2，ffmpeg avcodec_decode_video2( )分割错误

Question

我尝试解码AR.Drone 2.0 (http://ardrone2.parrot.com/)中的视频流已经有一段时间了，但没有成功。尽管有几个例子我一直在密切关注(我会粘贴链接，但我不允许)，但我无法逃避ffmpeg libavcodec库中的分段错误。我想我可能是在我正在构建的多线程结构中犯了什么错误，所以我删除了除了连接到无人机所需的最低限度之外的所有东西，从无人机中收集了一个框架，并将其发送到ffmpeg的avcodec_decode_video2()函数。

我编译了ffmpeg源代码(实际上我已经尝试了三个不同的版本！)并且可以获得显示无人机视频TCP流的ffplay实用程序。视频明显滞后，但至少我知道无人驾驶飞机并没有给我带来完全的胡言乱语。

以前有没有人遇到过这样的问题？是什么导致了这个分割错误，我能做些什么呢？有没有办法隔离ffmpeg上的测试，这样我就可以确定它是库，而不是我一直在做的事情？

耽误您时间，实在对不起。

带有我的代码的pastebin：http://pastebin.com/NYTf0NeT

有关我的ffmpeg和编译器设置的一些详细信息：

ffmpeg version 2.2.git Copyright (c) 2000-2014 the FFmpeg developers
  built on Mar  3 2014 18:05:42 with gcc 4.8 (Ubuntu 4.8.1-2ubuntu1~12.04)
  configuration: 
  libavutil      52. 66.100 / 52. 66.100
  libavcodec     55. 52.102 / 55. 52.102
  libavformat    55. 33.100 / 55. 33.100
  libavdevice    55. 10.100 / 55. 10.100
  libavfilter     4.  2.100 /  4.  2.100
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 18.100 /  0. 18.100

我的代码的输出和分段错误的回溯：

*********************** START ***********************



booting...

[h264 @ 0x604040] err{or,}_recognition separate: 1; 1

[h264 @ 0x604040] err{or,}_recognition combined: 1; 1

[h264 @ 0x604040] Unsupported bit depth: 0

asked for 40000 bytes, received packet of 1448 bytes

PaVE synchronized. YIPEEEEEEEEEEEEEEEEEEEEEEEE



---------------------------

Codec : H264

StreamID : 1 

Timestamp : 1031517 ms

Encoded dims : 640 x 368

Display dims : 640 x 360

Header size : 76

Payload size : 17583

Size of SPS inside payload : 14

Size of PPS inside payload : 10

Slices in the frame : 1

Frame Type / Number : IDR-Frame : 31467 : slide 1/1

---------------------------




gathering payload...

asked for 16211 bytes, received packet of 1448 bytes

gathering payload...

asked for 14763 bytes, received packet of 1448 bytes

gathering payload...

asked for 13315 bytes, received packet of 1448 bytes

gathering payload...

asked for 11867 bytes, received packet of 1448 bytes

gathering payload...

asked for 10419 bytes, received packet of 1448 bytes

gathering payload...

asked for 8971 bytes, received packet of 1448 bytes

gathering payload...

asked for 7523 bytes, received packet of 1448 bytes

gathering payload...

asked for 6075 bytes, received packet of 1448 bytes

gathering payload...

asked for 4627 bytes, received packet of 1448 bytes

gathering payload...

asked for 3179 bytes, received packet of 1448 bytes

gathering payload...

asked for 1731 bytes, received packet of 1448 bytes

gathering payload...

asked for 283 bytes, received packet of 283 bytes

payload complete, attempting to decode frame




Program received signal SIGSEGV, Segmentation fault.

0x00007ffff73fccba in ?? () from /usr/lib/x86_64-linux-gnu/libavcodec.so.53

(gdb) bt

#0  0x00007ffff73fccba in ?? () from /usr/lib/x86_64-linux-gnu/libavcodec.so.53

#1  0x00007ffff73fd8f5 in avcodec_decode_video2 () from /usr/lib/x86_64-linux-gnu/libavcodec.so.53

#2  0x000000000040159f in fetch_and_decode(int, parrot_video_encapsulation_t, AVCodecContext*, AVFrame*)

    ()

#3  0x00000000004019c6 in main ()

编辑:我用瓦兰来尝试更好地了解seg故障，并收到以下信息：

==4730== Invalid read of size 1
==4730==    at 0x5265CBA: ??? (in /usr/lib/x86_64-linux-gnu/libavcodec.so.53.35.0)
==4730==    by 0x52668F4: avcodec_decode_video2 (in /usr/lib/x86_64-linux-gnu/libavcodec.so.53.35.0)
==4730==    by 0x40140E: fetch_and_decode(int, AVCodecContext*, AVFrame*) (main.cpp:176)
==4730==    by 0x401757: main (main.cpp:273)
==4730==  Address 0x280056c46f9 is not stack'd, malloc'd or (recently) free'd
==4730== 
==4730== 
==4730== Process terminating with default action of signal 11 (SIGSEGV)
==4730==  Access not within mapped region at address 0x280056C46F9
==4730==    at 0x5265CBA: ??? (in /usr/lib/x86_64-linux-gnu/libavcodec.so.53.35.0)
==4730==    by 0x52668F4: avcodec_decode_video2 (in /usr/lib/x86_64-linux-gnu/libavcodec.so.53.35.0)
==4730==    by 0x40140E: fetch_and_decode(int, AVCodecContext*, AVFrame*) (main.cpp:176)
==4730==    by 0x401757: main (main.cpp:273)

“无效读取大小为1”指的是试图访问数组边界之外的字节。这是否意味着库试图访问我给它的数组范围之外的东西？我已经查过AVPkt了，这似乎很好。我还是很困惑！

Answer 1

我终于想明白了。要注意的关键是回溯跟踪中的特定FFMPEG共享库文件。这不是库的新的、手动编译的源代码版本。我没有正确地链接到更新的文件，而是链接到Ubuntu上的任何类型的默认设置。

解决这个问题需要重新编译FFMPEG，并确保我已经正确地链接到正确的共享库。

还有其他一些内存问题，但没有分段错误。我熨掉了一些更小的东西，并在这里粘贴结果：http://pastebin.com/rLEKB5Va

这样可以正确地捕获和显示视频。