[FFmpeg-devel] [Patch] Fix for static leaks in h264.c

Art Clarke aclarke
Wed Jun 25 18:17:52 CEST 2008


On Wed, Jun 25, 2008 at 10:11 AM, Art Clarke <aclarke at vlideshow.com> wrote:

>
> On Wed, Jun 25, 2008 at 10:06 AM, Art Clarke <aclarke at vlideshow.com>
> wrote:
>
>> On Wed, Jun 25, 2008 at 9:43 AM, Art Clarke <aclarke at vlideshow.com>
>> wrote:
>>
>>> Assuming I'm right in my analysis (always a dicey assumption) let me know
>>> which you'd prefer of the following two choices:
>>>
>>> Choice A: Simpler code but waste some stack space.
>>> Choice B: More complex code but be as efficient as possible with stack
>>> space.
>>>
>>> I'll adjust the patch accordingly if you choose Choice B.
>>>
>>> - Art
>>>
>>
>> Attached is my patch for Choice B.  I think it's more complicated to
>> understand, but is efficient with DATA SEGMENT (yes, I know not stack...
>> sorry) space.
>>
>> - Art
>>
>
> Scratch that.  I jumped the gun on that (didn't wait for a long-running
> test to finish) and it fails with the Choice B patch.  Let me figure that
> out, and I'll resubmit a choice B patch later.
>
> - Art


OK, here is my proposed Choice B (which I imagine Michael that you'll pick):

Same as Choice A (i.e. now we have a INIT_VLC_STATIC_WITH_TABLE) except:

- The varying static array is now a fully packed array (no wasted space).
- We compute offsets dynamically while initializing it based on the
..._tables_size array.
- We do one assert at the end of initialization to catch any "stupid
programmer bugs" like when I mistyped an offset in prior change.

This passes 100% of Vlideshow tests on h264-encoded video files.  All
resulting audio and video sounds and looks correct.
This passes 100% of ffmpeg regression tests (make fulltest) when run on
Fedora 7 static builds (which is the only way regression tests pass at all
for me).
There are no new log messages showing up.

- Art
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