[FFmpeg-devel] [PATCH] API changes in ffmpeg.c

[Michael Niedermayer]

On Fri, Apr 10, 2009 at 09:11:10PM +0200, Thilo Borgmann wrote:
> Michael Niedermayer schrieb:
>> On Fri, Apr 10, 2009 at 08:29:25PM +0200, Thilo Borgmann wrote:
>>   
>>> Michael Niedermayer schrieb:
>>>     
>>>>         
>>>>>>>            &picture, &got_picture, ptr, len);
>>>>>>> +                    ret = avcodec_decode_video2(ist->st->codec,
>>>>>>> +                                               &picture, 
>>>>>>> &got_picture, pkt);
>>>>>>>                         
>>>>>> Crash here.
>>>>>>                   
>>>>> This is revision 1 which fixes the crash during make test.
>>>>>             
>>>> probably ok if tested
>>>>
>>>>         
>>> Although applied, I tested it again using ffmpeg for transcoding the 
>>> corepng.avi into yuv format.
>>>
>>> This revealed a bug in my ffmpeg.c patch, but this bug breaks CorePNG 
>>> decoding only, since this is the only one using more information of the 
>>> provided packet than .data and .size attributes.
>>>
>>> FFplay is not broken as it uses no local AVPackets but the "original" 
>>> one.
>>>
>>> I attached a little patch for the time being, but I would propose to add 
>>> a "av_copy_packet" function into libavcodec/avpacket.c as future codecs 
>>> will also use more attributes of the avpacket and even others than just 
>>> the .flags attribute.
>>>     
>>
>> patch ok
>>   
> While I was thinking about a possible copy function, I realized that a 
> shallow copy would be enough here, so a simple avpkt = *pkt will do. A 
> function for a deep copy is not yet needed so I'm not going to add one.
>
> Reinspecting ffmpeg.c, revision 1 does solve it best in my eyes, so the 
> last patch here has become obsolete, if Michael agrees.
>
> Of course, this new patch has been tested using "make test" and the 
> transcoding into yuv.
>
> TB

> diff --git a/ffmpeg.c b/ffmpeg.c
> index 68f84fe..fb841c4 100644
> --- a/ffmpeg.c
> +++ b/ffmpeg.c
> @@ -1185,7 +1185,6 @@ static int output_packet(AVInputStream *ist, int ist_index,
>      int got_subtitle;
>      AVPacket avpkt;
>  
> -    av_init_packet(&avpkt);
>  
>      if(ist->next_pts == AV_NOPTS_VALUE)
>          ist->next_pts= ist->pts;
> @@ -1195,13 +1194,13 @@ static int output_packet(AVInputStream *ist, int ist_index,
>          avpkt.data = NULL;
>          avpkt.size = 0;
>          goto handle_eof;
> +    } else {
> +        avpkt = *pkt;
>      }

i suspect that this can end with partially initialized avpkt

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
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