[Libav-user] (AVStream *)av_malloc(sizeof(AVStream)) crashed the application

[Wenpeng Zhou]

Hi Chandranath and Geek.Song

 

Thanks!

I see.

 

I fixed as your suggested.

 

From: libav-user-bounces at ffmpeg.org [mailto:libav-user-bounces at ffmpeg.org]
On Behalf Of Chandranath Bhattacharyya
Sent: 30. lokakuuta 2012 13:28
To: This list is about using libavcodec, libavformat, libavutil, libavdevice
and libavfilter.
Subject: Re: [Libav-user] (AVStream *)av_malloc(sizeof(AVStream)) crashed
the application

 

>> Hi Chandranath

 

>> Thanks!

 

>> But I already allocated memory for the pointer *ic_enc_mjpeg

                OK. Sorry. I did not realize you meant the crash occurred
even after allocation.

 

>> AVFormatContext *ic_enc_mjpeg;

>> ic_enc_mjpeg = (AVFormatContext *)av_malloc(sizeof(AVFormatContext));

 

>> Then I tried to allocate the memory for ic_enc_mjpeg->streams[0], then it
crashed.

 

streams variable inside AVFormatContext is AVStream **. So the allocation of
AVFormatContext using av_malloc is not supposed to initialize/allocate it.
Hence the crash.

 

Check the documentation in header avformat.h for more info. 

 

The crash can be fixed by the following code. 

 

AVFormatContext *ic_enc_mjpeg;

ic_enc_mjpeg = (AVFormatContext *)av_malloc(sizeof(AVFormatContext));

ic_enc_mjpeg->streams = (AVStream **)av_malloc(sizeof(AVStream *)); // ç DO
THIS. 

ic_enc_mjpeg->nb_streams = 1; // OR WHATEVER.

ic_enc_mjpeg->streams[0] = (AVStream *)av_malloc(sizeof(AVStream));

 

Regards,

Chandranath

 

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