[Ffmpeg-devel] [PATCH] ASF Stream bitrate GUID parsing....

[Ryan Martell]

Hi--

On Jan 4, 2007, at 9:27 PM, Ryan Martell wrote:

> Hi...
>
> On Jan 4, 2007, at 6:59 PM, Michael Niedermayer wrote:
>
>> Hi
>>
>> On Thu, Jan 04, 2007 at 04:45:22PM -0600, Ryan Martell wrote:
>>> Hi--
>>>
>>> To support my native mms code, I need to parse the bitrate GUID
>>> header of the ASF file if it's present.  This small patch adds that
>>> information to the ASFContext.
>>>
>>> A couple of quick notes:
>>>
>>> 1) The indentation is actually correct now (the block below is
>>> indented incorrectly) on the lines:
>>> -       } else if (!memcmp(&g, &extended_content_header, sizeof
>>> (GUID))) {
>>> +        } else if (!memcmp(&g, &stream_bitrate_guid, sizeof 
>>> (GUID))) {
>>>
>>> 2) I removed:
>>>  ASFStream streams[128];     /* it's max number and it's not that
>>> big */
>>>> from the ASFContext, as it was unused (and big).  I replaced it  
>>>> with
>>> a 128 uint32_t array, which seems fair.

Attached is another patch; I couldn't remove streams, as it was used  
by asf_enc.c, and I the deps aren't quite right, so I didn't catch it  
until I did a full rebuild.

>> [...]
>>> +        } else if (!memcmp(&g, &stream_bitrate_guid, sizeof 
>>> (GUID))) {
>>> +            uint16_t streams = get_le16(pb);
>>> +            int j;
>>> +
>>> +#ifdef DEBUG
>>> +            av_log(NULL, AV_LOG_ERROR, "stream bitrate properties 
>>> \n");
>>> +            av_log(NULL, AV_LOG_ERROR, "streams %d\n", streams);
>>> +#endif
>>> +
>>> +            for(j = 0; j < streams; j++) {
>>> +                uint16_t flags;
>>> +                uint32_t bitrate;
>>> +                int stream_id;
>>> +
>>> +                flags= get_le16(pb);
>>> +                bitrate= get_le32(pb);
>>> +                stream_id= (flags & 0x7f);
>>> +#ifdef DEBUG
>>> +                av_log(NULL, AV_LOG_ERROR, "flags: 0x%x stream  
>>> id %d, bitrate %d\n", flags, stream_id, bitrate);
>>> +#endif
>>> +                asf->stream_bitrates[stream_id-1]= bitrate;
>>
>> the -1 causes a possible write prior to the array
>
> stream_id of zero is invalid; attached patch ignores bitrate if the  
> stream id is zero.

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