[FFmpeg-devel] [PATCH] Parsing ALS object type in MPEG-4

[Ronald S. Bultje]

Hi Reimar,

On Thu, Aug 20, 2009 at 2:22 AM, Reimar
D?ffinger<Reimar.Doeffinger at gmx.de> wrote:
> On Wed, Aug 19, 2009 at 08:18:19PM -0400, Ronald S. Bultje wrote:
>> On Wed, Aug 19, 2009 at 8:10 PM, Thilo
>> Borgmann<thilo.borgmann at googlemail.com> wrote:
>> >>> + ? ?if (get_bits_long(gb, 32) != 0x414C5300)
>> >> MKBETAG('A','L','S','\0')
>> > Done.
>> [..]
>> > + ? ? ? ?if (show_bits_long(&gb, 24) != 0x414C53) {
>>
>> same here (MKBETAG(0, 'A', 'L', 'S'))?
>
> How about AV_RB24("ALS") and AV_RL24("ALS") ?

(Completely irrelevant performance-wise, but ...) do they actually
expand to the same asm (with a reasonably modern gcc -O3-style
compiler)? Or is the string part of the generated asm for the second
case / is the first therefore in fact more efficient?

(I've always preferred the MK*TAG() over string-parsing with the
assumption that it'd be more efficient...)

Ronald