Hi,
> > The problem:
> > Some of the vobs have ac3 sound with only 2 channels (A52_DOLBY format).
> > Liba52 does not "upmix" the output to 5+1 channels, so this causes a lot of
> > garbage in the sound output (this is described in liba52.txt).
>
> i think this should be fixed in liba52's downsample.c, or at worst case, at
> resample.c. (there are upsampling code too at downsample.c)
look at dec_audio.c:
switch(sh_audio->channels){
case 1: flags=A52_MONO; break;
// case 2: flags=A52_STEREO; break;
case 2: flags=A52_DOLBY; break;
// case 3: flags=A52_3F; break;
case 3: flags=A52_2F1R; break;
case 4: flags=A52_2F2R; break; // 2+2
case 5: flags=A52_3F2R; break;
case 6: flags=A52_3F2R|A52_LFE; break; // 5.1
}
flags|=A52_ADJUST_LEVEL;
sh_audio->a_in_buffer_len=0;
if (a52_frame (&a52_state, sh_audio->a_in_buffer, &flags, &level,bias))
mp_msg(MSGT_DECAUDIO,MSGL_WARN,"a52: error decoding frame\n");
break;
}
it will setup channel mode depending on user-spefied number of channels.
liba52 should down/upmix any format to this mode.
you mean, it fails here? (you request A52_3F2R|A52_LFE, but it does A52_DOLBY ?)
if yes, then it's liba52's bug/limitation. i think it's bug, as downmix.c
seems to have lots of conversion for all possible cases (even for mono->6ch)
you should add printf to print value of 'flags' before and after the call to
decoder:
if (a52_frame (&a52_state, sh_audio->a_in_buffer, &flags, &level, bias))
to see if it changes 'flags'.
please tell me the results, i have no such card.
(really i have, sb live, but i got errors when requesting more
than 2 channels. maybe i should use different driver, from creative site or
alsa??? - i'm using oss driver of 2.4.7)
A'rpi / Astral & ESP-team
--
mailto:arpi at thot.banki.hu
http://esp-team.scene.hu