[FFmpeg-devel] [PATCH] avformat/movenc: Reduce size of the allocated MOVIentry array

[James Almer]

On 3/26/2020 11:22 AM, Anton Khirnov wrote:
> Quoting James Almer (2020-03-26 15:18:53)
>> On 3/26/2020 11:06 AM, Anton Khirnov wrote:
>>> Quoting James Almer (2020-03-25 18:56:44)
>>>> Increase it in a linear way instead.
>>>> Helps reduce memory usage, especially on long, non fragmented output.
>>>>
>>>> Signed-off-by: James Almer <jamrial at gmail.com>
>>>> ---
>>>> An alternative is using av_fast_realloc(), in a similar fashion as
>>>> ff_add_index_entry(), which will keep the memory usage more closely tied to the
>>>> amount of entries needed, but the amount of reallocations will be much higher,
>>>> so i don't know if the tradeof is beneficial.
>>>
>>> Wait, wouldn't fast_realloc() do pretty much the same as your patch? Why
>>> should the number of reallocations be higher?
>>
>> I meant mimicking the behavior of ff_add_index_entry(), doing something like
>>
>> cluster = av_fast_realloc(trk->cluster,
>>                           &trk->cluster_capacity,
>>                           (trk->entry + 1) * sizeof(*trk->cluster));
>> trk->cluster = cluster;
>>
>> Which will get rid of the fixed MOV_INDEX_CLUSTER_SIZE increase per
>> realloc, and resulting in more, smaller size increment reallocs (but of
>> course not after every single new entry, which is the entire point of
>> av_fast_realloc()).
> 
> Ah, got it.
> 
> I'd say your patch is better, but it probably doesn't matter much.

Applied then, thanks.