[FFmpeg-devel] [PATCH] probe max read size

[Baptiste Coudurier]

Michael Niedermayer wrote:
> On Wed, Jun 24, 2009 at 04:15:22PM -0700, Baptiste Coudurier wrote:
>> Michael Niedermayer wrote:
>>> On Wed, Jun 24, 2009 at 12:47:14PM -0700, Baptiste Coudurier wrote:
>>>> Hi Michael,
>>>>
>>>> Michael Niedermayer wrote:
>>>>> On Wed, Jun 03, 2009 at 03:29:48PM -0700, Baptiste Coudurier wrote:
>>>>>> Michael Niedermayer wrote:
>>>>>>> On Mon, Jun 01, 2009 at 09:50:47PM -0700, Baptiste Coudurier wrote:
>>>>>>>> Michael Niedermayer wrote:
>>>>>>>>> On Mon, Jun 01, 2009 at 03:37:55PM -0700, Baptiste Coudurier wrote:
>>>>>>>>>> Michael Niedermayer wrote:
>>>>>>>>>>> On Mon, Jun 01, 2009 at 12:36:54PM -0700, Baptiste Coudurier wrote:
>>>>>>>>>>>> Michael Niedermayer wrote:
>>>>>>>>>>>>> On Sun, May 31, 2009 at 02:53:34AM -0700, Baptiste Coudurier wrote:
> [...]
>>>>>>>> Patch attached. I believe using probesize is a good opportunity and I
>>>>>>>> plan to replace MAX_READ_SIZE by probesize too, changing probesize
>>>>>>>> default to 5000000.
>>>>>>>>
>>>>>>>> I find the FFMAX a bit ugly but I feel it would be safer.
>>>>>>> [...]
>>>>>>>> @@ -532,8 +534,13 @@ int av_read_packet(AVFormatContext *s, AVPacket *p
>>>>>>>>          if (pktl) {
>>>>>>>>              *pkt = pktl->pkt;
>>>>>>>>              if(s->streams[pkt->stream_index]->codec->codec_id != CODEC_ID_PROBE ||
>>>>>>>> -               !s->streams[pkt->stream_index]->probe_packets){
>>>>>>>> +               !s->streams[pkt->stream_index]->probe_packets ||
>>>>>>>> +               s->raw_packet_buffer_remaining_size <= 0){
>>>>>>>> +                AVProbeData *pd = &st->probe_data;
>>>>>>>> +                av_freep(&pd->buf);
>>>>>>>> +                pd->buf_size = 0;
>>>>>>>>                  s->raw_packet_buffer = pktl->next;
>>>>>>>> +                s->raw_packet_buffer_remaining_size += pkt->size;
>>>>>>>>                  av_free(pktl);
>>>>>>>>                  return 0;
>>>>>>>>              }
>>>>>>>> @@ -567,6 +574,8 @@ int av_read_packet(AVFormatContext *s, AVPacket *p
>>>>>>>>              return ret;
>>>>>>>>  
>>>>>>>>          add_to_pktbuf(&s->raw_packet_buffer, pkt, &s->raw_packet_buffer_end);
>>>>>>>> +        s->raw_packet_buffer_remaining_size =
>>>>>>>> +            FFMAX(0, s->raw_packet_buffer_remaining_size - pkt->size);
>>>>>>>>  
>>>>>>>>          if(st->codec->codec_id == CODEC_ID_PROBE){
>>>>>>>>              AVProbeData *pd = &st->probe_data;
>>>>>>> is the combination of FFMAX here and the += pkt->size; above not able to
>>>>>>> change raw_packet_buffer_remaining_size to a value that is beyond the
>>>>>>> initial limit ?
>>>>>> That's possible indeed, I was wondering is this would be safe. If you
>>>>>> think it's safer to limit it as well, here is an updated patch.
>>>>> i think it should be possible to remove both FFMIN&MAX
>>>>> we just have to check the remaining size against the packet size instead
>>>>> of against 0 then we can always saftely subtract it
>>>> I'm not sure to understand what you mean here.
>>>> Can you please clarify by code ?
>>>>
>>>> Do you mean
>>>> if (s->raw_packet_buffer_remaining_size >= pkt->size)
>>>>     remaining_size -= pkt->size;
>>>>
>>>> ?
>>>>
>>>> How would you change the check above ?
>>> what i meant is to replace
>>> if(raw_packet_buffer_remaining_size <= 0)
>>>     end
>>> by
>>> if(raw_packet_buffer_remaining_size < next_packet)
>>>     end
>>>
>>> that way the next packet will always fit in raw_packet_buffer_remaining_size
>>> and can be subtracted without MIN/MAX
>> Ok, patch attached.
>>
>> -- 
>> Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
>> Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
>> FFmpeg maintainer                                  http://www.ffmpeg.org
> 
>>  avformat.h |    7 +++++++
>>  utils.c    |   11 ++++++++++-
>>  2 files changed, 17 insertions(+), 1 deletion(-)
>> 79a80d827ddafdbe8d82d00c650dd277711a76f2  raw_packet_buffer2.patch
> 
> ok

Great applied.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
FFmpeg maintainer                                  http://www.ffmpeg.org