static int decode_audio(struct dec_audio *da, struct mp_audio *buffer, int maxlen)
{
struct ad_mpg123_context *con = da->priv;
void *buf = buffer->planes[0];
int ret;
if (con->new_format) {
ret = set_format(da);
if (ret == MPG123_OK) {
return 0; // let caller handle format change
} else if (ret == MPG123_NEED_MORE) {
con->need_data = true;
} else {
goto mpg123_fail;
}
}
if (con->need_data) {
if (feed_new_packet(da) < 0)
return -1;
}
if (!mp_audio_config_equals(&da->decoded, buffer))
return 0;
size_t got_now = 0;
ret = mpg123_replace_buffer(con->handle, buf, maxlen * con->sample_size);
if (ret != MPG123_OK)
goto mpg123_fail;
ret = mpg123_decode_frame(con->handle, NULL, NULL, &got_now);
int got_samples = got_now / con->sample_size;
buffer->samples += got_samples;
da->pts_offset += got_samples;
if (ret == MPG123_NEW_FORMAT) {
con->new_format = true;
} else if (ret == MPG123_NEED_MORE) {
con->need_data = true;
} else if (ret != MPG123_OK && ret != MPG123_DONE) {
goto mpg123_fail;
}
update_info(da);
return 0;
mpg123_fail:
MP_ERR(da, "mpg123 decoding error: %s\n",
mpg123_strerror(con->handle));
return -1;
}
/* This tries to extract a requested amount of decoded data.
* Even when you request 0 bytes, it will feed enough input so that
* the decoder _could_ have delivered something.
* Returns byte count >= 0, -1 on error.
*
* Thoughts on exact pts keeping:
* We have to assume that MPEG frames are cut in pieces by packet boundaries.
* Also, it might be possible that the first packet does not contain enough
* data to ensure initial stream sync... or re-sync on erroneous streams.
* So we need something robust to relate the decoded byte count to the correct
* time stamp. This is tricky, though. From the outside, you cannot tell if,
* after having fed two packets until the first output arrives, one should
* start counting from the first packet's pts or the second packet's.
* So, let's just count from the last fed package's pts. If the packets are
* exactly cut to MPEG frames, this will cause one frame mismatch in the
* beginning (when mpg123 peeks ahead for the following header), but will
* be corrected with the third frame already. One might add special code to
* not increment the base pts past the first packet's after a resync before
* the first decoded bytes arrived. */
static int decode_a_bit(sh_audio_t *sh, unsigned char *buf, int count)
{
int ret = MPG123_OK;
int got = 0;
struct ad_mpg123_context *con = sh->context;
/* There will be one MPG123_NEW_FORMAT message on first open.
* This will be handled in init(). */
do {
size_t got_now = 0;
/* Feed the decoder. This will only fire from the second round on. */
if (ret == MPG123_NEED_MORE) {
int incount;
double pts;
unsigned char *inbuf;
/* Feed more input data. */
incount = ds_get_packet_pts(sh->ds, &inbuf, &pts);
if (incount <= 0)
break; /* Apparently that's it. EOF. */
/* Next bytes from that presentation time. */
if (pts != MP_NOPTS_VALUE) {
sh->pts = pts;
sh->pts_bytes = 0;
}
#ifdef AD_MPG123_FRAMEWISE
/* Have to use mpg123_feed() to avoid decoding here. */
ret = mpg123_feed(con->handle, inbuf, incount);
#else
/* Do not use mpg123_feed(), added in later libmpg123 versions. */
ret = mpg123_decode(con->handle, inbuf, incount, NULL, 0, NULL);
#endif
if (ret == MPG123_ERR)
break;
}
/* Theoretically, mpg123 could return MPG123_DONE, so be prepared.
* Should not happen in our usage, but it is a valid return code. */
else if (ret == MPG123_ERR || ret == MPG123_DONE)
break;
/* Try to decode a bit. This is the return value that counts
* for the loop condition. */
#ifdef AD_MPG123_FRAMEWISE
if (!buf) { /* fake call just for feeding to get format */
ret = mpg123_getformat(con->handle, NULL, NULL, NULL);
} else { /* This is the decoding. One frame at a time. */
ret = mpg123_replace_buffer(con->handle, buf, count);
if (ret == MPG123_OK)
ret = mpg123_decode_frame(con->handle, NULL, NULL, &got_now);
}
#else
ret = mpg123_decode(con->handle, NULL, 0, buf + got, count - got,
&got_now);
#endif
got += got_now;
sh->pts_bytes += got_now;
#ifdef AD_MPG123_FRAMEWISE
} while (ret == MPG123_NEED_MORE || (got == 0 && count != 0));
#else
} while (ret == MPG123_NEED_MORE || got < count);
/****************************************************************************
* DecodeBlock: the whole thing
****************************************************************************/
static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
{
int i_err;
block_t *p_block = pp_block ? *pp_block : NULL;
decoder_sys_t *p_sys = p_dec->p_sys;
if( !pp_block || !p_block )
return NULL;
if( p_block->i_buffer == 0 )
return NULL;
if( !date_Get( &p_sys->end_date ) && p_block->i_pts <= VLC_TS_INVALID )
{
/* We've just started the stream, wait for the first PTS. */
msg_Dbg( p_dec, "waiting for PTS" );
goto error;
}
if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY | BLOCK_FLAG_CORRUPTED) )
{
date_Set( &p_sys->end_date, 0 );
if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
goto error;
}
/* Feed mpg123 with raw data */
i_err = mpg123_feed( p_sys->p_handle, p_block->p_buffer,
p_block->i_buffer );
if( i_err != MPG123_OK )
{
msg_Err( p_dec, "mpg123_feed failed: %s", mpg123_plain_strerror( i_err ) );
goto error;
}
/* Get details about the stream */
i_err = mpg123_info( p_sys->p_handle, &p_sys->frame_info );
if( i_err == MPG123_NEED_MORE )
{
/* Need moar data */
goto error;
}
else if( i_err != MPG123_OK )
{
msg_Err( p_dec, "mpg123_info failed: %s", mpg123_plain_strerror( i_err ) );
goto error;
}
/* Configure the output */
p_block->i_nb_samples = mpg123_spf( p_sys->p_handle );
p_dec->fmt_out.i_bitrate = p_sys->frame_info.bitrate * 1000;
switch( p_sys->frame_info.mode )
{
case MPG123_M_STEREO:
case MPG123_M_JOINT:
p_dec->fmt_out.audio.i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT;
break;
case MPG123_M_DUAL:
p_dec->fmt_out.audio.i_original_channels = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
| AOUT_CHAN_DUALMONO;
break;
case MPG123_M_MONO:
p_dec->fmt_out.audio.i_original_channels = AOUT_CHAN_CENTER;
break;
default:
msg_Err( p_dec, "Unknown mode");
goto error;
}
p_dec->fmt_out.audio.i_physical_channels =
p_dec->fmt_out.audio.i_original_channels & AOUT_CHAN_PHYSMASK;
/* Date management */
if( p_dec->fmt_out.audio.i_rate != p_sys->frame_info.rate )
{
p_dec->fmt_out.audio.i_rate = p_sys->frame_info.rate;
date_Init( &p_sys->end_date, p_dec->fmt_out.audio.i_rate, 1 );
date_Set( &p_sys->end_date, 0 );
}
if( p_block->i_pts > VLC_TS_INVALID &&
p_block->i_pts != date_Get( &p_sys->end_date ) )
{
date_Set( &p_sys->end_date, p_block->i_pts );
}
/* Request a new audio buffer */
block_t *p_out = decoder_NewAudioBuffer( p_dec, p_block->i_nb_samples );
if( unlikely( !p_out ) )
goto error;
/* Configure the buffer */
p_out->i_nb_samples = p_block->i_nb_samples;
p_out->i_dts = p_out->i_pts = date_Get( &p_sys->end_date );
p_out->i_length = date_Increment( &p_sys->end_date, p_block->i_nb_samples )
- p_out->i_pts;
/* Make mpg123 write directly into the VLC output buffer */
i_err = mpg123_replace_buffer( p_sys->p_handle, p_out->p_buffer, p_out->i_buffer );
if( i_err != MPG123_OK )
{
msg_Err( p_dec, "could not replace buffer: %s", mpg123_plain_strerror( i_err ) );
block_Release( p_out );
goto error;
}
*pp_block = NULL; /* avoid being fed the same packet again */
/* Do the actual decoding now */
i_err = mpg123_decode_frame( p_sys->p_handle, NULL, NULL, NULL );
if( i_err != MPG123_OK )
{
if( i_err != MPG123_NEW_FORMAT )
msg_Err( p_dec, "mpg123_decode_frame error: %s", mpg123_plain_strerror( i_err ) );
block_Release( p_out );
goto error;
}
block_Release( p_block );
return p_out;
error:
block_Release( p_block );
return NULL;
}
/****************************************************************************
* DecodeBlock: the whole thing
****************************************************************************/
static int DecodeBlock( decoder_t *p_dec, block_t *p_block )
{
int i_err;
decoder_sys_t *p_sys = p_dec->p_sys;
block_t *p_out = NULL;
if( !p_sys->b_opened )
{
if( p_block )
block_Release( p_block );
return VLCDEC_ECRITICAL;
}
/* Feed input block */
if( p_block != NULL )
{
if( !date_Get( &p_sys->end_date ) && p_block->i_pts <= VLC_TS_INVALID )
{
/* We've just started the stream, wait for the first PTS. */
msg_Dbg( p_dec, "waiting for PTS" );
goto end;
}
if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
{
Flush( p_dec );
if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )
goto end;
}
/* Feed mpg123 with raw data */
i_err = mpg123_feed( p_sys->p_handle, p_block->p_buffer,
p_block->i_buffer );
if( i_err != MPG123_OK )
{
msg_Err( p_dec, "mpg123_feed failed: %s",
mpg123_plain_strerror( i_err ) );
goto end;
}
}
/* Fetch a new output block (if possible) */
if( !p_sys->p_out
|| p_sys->p_out->i_buffer != mpg123_outblock( p_sys->p_handle ) )
{
if( p_sys->p_out )
block_Release( p_sys->p_out );
/* Keep the output buffer for next calls in case it's not used (in case
* of MPG123_NEED_MORE status) */
p_sys->p_out = block_Alloc( mpg123_outblock( p_sys->p_handle ) );
if( unlikely( !p_sys->p_out ) )
return VLCDEC_SUCCESS;
}
/* Do the actual decoding now */
size_t i_bytes = 0;
while( true )
{
/* Make mpg123 write directly into the VLC output buffer */
i_err = mpg123_replace_buffer( p_sys->p_handle, p_sys->p_out->p_buffer,
p_sys->p_out->i_buffer );
if( i_err != MPG123_OK )
{
msg_Err( p_dec, "could not replace buffer: %s",
mpg123_plain_strerror( i_err ) );
block_Release( p_sys->p_out );
p_sys->p_out = NULL;
return VLCDEC_SUCCESS;
}
i_err = mpg123_decode_frame( p_sys->p_handle, NULL, NULL, &i_bytes );
if( i_err != MPG123_OK )
{
if( i_err == MPG123_NEW_FORMAT )
{
if( UpdateAudioFormat( p_dec ) != VLC_SUCCESS )
goto end;
else
continue;
}
else if( i_err != MPG123_NEED_MORE )
msg_Err( p_dec, "mpg123_decode_frame error: %s",
mpg123_plain_strerror( i_err ) );
}
else if( p_dec->fmt_out.audio.i_rate == 0 )
{
msg_Warn( p_dec, "mpg123_decode_frame returned valid frame without "
"updating the format" );
if( UpdateAudioFormat( p_dec ) != VLC_SUCCESS )
goto end;
}
break;
}
if( p_block && p_block->i_pts > VLC_TS_INVALID &&
p_block->i_pts != date_Get( &p_sys->end_date ) )
date_Set( &p_sys->end_date, p_block->i_pts );
if( i_bytes == 0 )
goto end;
assert( p_dec->fmt_out.audio.i_rate != 0 );
p_out = p_sys->p_out;
p_sys->p_out = NULL;
assert( p_out->i_buffer >= i_bytes );
p_out->i_buffer = i_bytes;
p_out->i_nb_samples = p_out->i_buffer * p_dec->fmt_out.audio.i_frame_length
/ p_dec->fmt_out.audio.i_bytes_per_frame;
/* Configure the buffer */
p_out->i_dts = p_out->i_pts = date_Get( &p_sys->end_date );
p_out->i_length = date_Increment( &p_sys->end_date, p_out->i_nb_samples )
- p_out->i_pts;
end:
if( p_block )
block_Release( p_block );
if( p_out != NULL )
decoder_QueueAudio( p_dec, p_out );
return VLCDEC_SUCCESS;
}
