[FFmpeg-devel] [PATCH] avutil/crc: avoid needless space wastage of hardcoded crc table

Ganesh Ajjanagadde gajjanagadde at gmail.com
Mon Nov 30 03:50:05 CET 2015


On Sun, Nov 29, 2015 at 9:45 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> Hi,
>
> On Sun, Nov 29, 2015 at 9:41 PM, Ganesh Ajjanagadde <gajjanagadde at gmail.com>
> wrote:
>>
>> There was no reason AFAIK for making AV_CRC_24_IEEE 12. This simply
>> resulted in wasted space under --enable-hardcoded-tables:
>> dynamic: 1318672 libavutil/libavutil.so.55
>> old    : 1330680 libavutil/libavutil.so.55
>> new    : 1326488 libavutil/libavutil.so.55
>>
>> Minor version number is bumped.
>>
>> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>> ---
>>  libavutil/crc.h     | 2 +-
>>  libavutil/version.h | 2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavutil/crc.h b/libavutil/crc.h
>> index e86bf1d..61592df 100644
>> --- a/libavutil/crc.h
>> +++ b/libavutil/crc.h
>> @@ -40,7 +40,7 @@ typedef enum {
>>      AV_CRC_32_IEEE,
>>      AV_CRC_32_IEEE_LE,  /*< reversed bitorder version of AV_CRC_32_IEEE
>> */
>>      AV_CRC_16_ANSI_LE,  /*< reversed bitorder version of AV_CRC_16_ANSI
>> */
>> -    AV_CRC_24_IEEE = 12,
>> +    AV_CRC_24_IEEE,
>>      AV_CRC_MAX,         /*< Not part of public API! Do not use outside
>> libavutil. */
>>  }AVCRCId;
>
>
> I support the idea, but this breaks ABI. You need to do this under a version
> bump, see libavutil/version.h for templates.

Sorry, can you be a little more explicit: I bump the minor version
number here of avutil. Do you mean to use AV_VERSION_INT and friends
to check and accordingly place ifdefy?

>
> Ronald


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