Andy Lo-A-Foe wrote:
> On Wed, Aug 14, 2002 at 06:34:15PM +0200, Emmanuel Fleury wrote:
>
>
>>But, does it support more than mono and stereo (I mean, is the
>>5.1 mode effective ?).
>
>
> I have only ever tested it in mono. Not sure 5.1 works. My original
> interests were real-time AC3 encoding. However, it looks like even a
> 1.4GHZ Athlon is too slow to do real-time *mono* AC-3 encoding, let
> alone full blown 5.1 :/ .. at least with the ffmpeg codebase
Actually my interest is more to encode AC-3 in mode 5.1 and play it
afterward (just for musical stuff).
But, straight from the ac3enc.h file, it seems that ffmpeg is able
to manage with a pretty high number of channels.
I think there is some hope. :-)
#define AC3_FRAME_SIZE (6*256)
#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
#define AC3_MAX_CHANNELS 6
typedef struct AC3EncodeContext {
PutBitContext pb;
int nb_channels;
int nb_all_channels;
int lfe_channel;
int bit_rate;
int sample_rate;
int bsid;
int frame_size_min; /* minimum frame size in case rounding is
necessary */
int frame_size; /* current frame size in words */
int halfratecod;
int frmsizecod;
int fscod; /* frequency */
int acmod;
int lfe;
int bsmod;
short last_samples[AC3_MAX_CHANNELS][256];
int chbwcod[AC3_MAX_CHANNELS];
int nb_coefs[AC3_MAX_CHANNELS];
Regards
--
Emmanuel
To iterate is human; to recurse, is divine.
-- Unknown
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