Commit 18597150 authored by Jean-Paul Saman's avatar Jean-Paul Saman
Browse files

Changes made to mad plugin:

+ libmad_input now takes one frame at a time (see mad_adec.h for defines)
+ audio_linear_dither() gives better sound quality then s24_to_s16_pcm(),
  but also makes audio artefacts louder so disabled it for now (see file
  mad_libmad.c)
+ cleaned up libmad_output (see file mad_libmad.c)
+ cleaned up InitThread (see file mad_adec.c)
+ Made buffer size match libmad's expectations (see file mad_adec.h)
+ updated documentation
parent ae09661b
......@@ -5,18 +5,22 @@ Directories:
============
vlc/plugins/mad : mad audio decoder plugin for vlc
Interface functions to implement in mad plugin are:
=========
decoder_Probe
decoder_Run
adec_mad_InitThred
adec_mad_EndThread
libmad_input
libmad_output
libmad_header
libmad_messages
libmad_error
Interface functions
===================
The following interface functions are implemented in the mad plugin.
decoder_Probe : vlc probes for plugin capabilities
decoder_Run : vlc starts a decoder plugin by calling this function
InitThread : routine to do some initializations
EndThread : cleanup function
The following functions are callback functions for the mad decoder library:
libmad_input : called when input data is needed
libmad_output : called whenever a frame has been decoded
libmad_header : called upon decoding of only a frame header
libmad_messages : libmad messages
libmad_error : called whenever an error occured during the decoding process
Design: (ASCII art)
=======
......@@ -35,10 +39,10 @@ initializing, starting and stopping them.
_______________
^
|
________________________
| <decoder interface> |
| vlc plugin interface |
________________________
________________________
| <decoder interface> |
| vlc plugin interface |
________________________
Interface view:
......@@ -49,6 +53,7 @@ Interface view:
-----------------------
Rationel:
========
Keeping libmad as a separate library on the system, either dynamic or statically linked in, makes maintenance so much simpeler.
Merging with a new libmad version should be straight forward as long as the interface stays stable.
There is another benefit: Disk (actually flash ROM) resources and memory are very limited on a iPaq.
......
......@@ -24,7 +24,7 @@ commit to current vlc-dev tree in CVS at VideoLan
[5 - all ready done by Christophe Massiot]
make cross-compile possible for vlc without interface. With interface it is to damn difficult to do cross-compilation.
[6 - ]
[6 - busy ]
extending mad plugin with more features
do fancy stuff (enable MP3 decoding)
......@@ -44,12 +44,3 @@ incorporate new libmad version if possible
see 7
see 8
[10 - ]
rewrite the audio decoding process by using a lower level API. In this way the decoding process can be steered and tuned better.
Hopefully it will get rid of audio cracks and jitter.
[11 - ]
test plugin: native Intel, native iPaq
[12 - ]
commit to vlc-dev tree.
\ No newline at end of file
......@@ -165,6 +165,7 @@ static int InitThread( mad_adec_thread_t * p_mad_adec )
/* Initialize the libmad decoder structures */
p_mad_adec->libmad_decoder = (struct mad_decoder*) malloc(sizeof(struct mad_decoder));
if (p_mad_adec->libmad_decoder == NULL) {
intf_ErrMsg ( "mad_adec error: not enough memory "
"for decoder_InitThread() to allocate p_mad_adec->libmad_decder" );
......@@ -185,16 +186,14 @@ static int InitThread( mad_adec_thread_t * p_mad_adec )
libmad_input, /* input_func */
0, /* header_func */
0, /* filter */
libmad_output, /* output_func */
0, /* error */
libmad_output, /* output_func */
0, /* error */
0); /* message */
mad_decoder_options(p_mad_adec->libmad_decoder, MAD_OPTION_IGNORECRC);
mad_timer_reset(&p_mad_adec->libmad_timer);
/*
* Initialize the output properties
*/
/* output fifo will be created when needed */
p_mad_adec->p_aout_fifo=NULL;
intf_ErrMsg("mad_adec debug: mad decoder thread %p initialized", p_mad_adec);
......
......@@ -23,8 +23,9 @@
// FIXME: Ugly define inside a decoder
#define ADEC_FRAME_SIZE (2*1152)
#define MAD_BUFFER_SIZE (ADEC_FRAME_SIZE*2)
//#define MAD_BUFFER_SIZE (MAD_BUFFER_MDLEN*2)
// MAD_BUFFER_MDLEN (511 + 2048 + MAD_BUFLEN_GUARD) and MAD_BUFLEN_GUARD is 8
#define MAD_BUFFER_SIZE (MAD_BUFFER_MDLEN)
//#define MAD_BUFFER_SIZE (ADEC_FRAME_SIZE*2)
#define MAD_OUTPUT_SIZE (ADEC_FRAME_SIZE*2)
typedef struct mad_adec_thread_s
......
......@@ -47,8 +47,8 @@
enum mad_flow libmad_input(void *data, struct mad_stream *p_libmad_stream)
{
mad_adec_thread_t *p_mad_adec = (mad_adec_thread_t *) data;
size_t ReadSize, Remaining;
unsigned char *ReadStart;
size_t ReadSize, Remaining;
unsigned char *ReadStart;
if ( p_mad_adec->p_fifo->b_die == 1 ) {
intf_ErrMsg( "mad_adec error: libmad_input stopping libmad decoder" );
......@@ -65,35 +65,38 @@ enum mad_flow libmad_input(void *data, struct mad_stream *p_libmad_stream)
*/
if ((p_libmad_stream->buffer==NULL) || (p_libmad_stream->error==MAD_ERROR_BUFLEN))
{
/* libmad does not consume all the buffer it's given. Some
* datas, part of a truncated frame, is left unused at the
* end of the buffer. Those datas must be put back at the
* beginning of the buffer and taken in account for
* refilling the buffer. This means that the input buffer
* must be large enough to hold a complete frame at the
* highest observable bit-rate (currently 448 kb/s). XXX=XXX
* Is 2016 bytes the size of the largest frame?
* (448000*(1152/32000))/8
*/
if(p_libmad_stream->next_frame!=NULL)
{
Remaining=p_libmad_stream->bufend-p_libmad_stream->next_frame;
memmove(p_mad_adec->buffer,p_libmad_stream->next_frame,Remaining);
ReadStart=p_mad_adec->buffer+Remaining;
ReadSize=(MAD_BUFFER_SIZE)-Remaining;
/* libmad does not consume all the buffer it's given. Some
* datas, part of a truncated frame, is left unused at the
* end of the buffer. Those datas must be put back at the
* beginning of the buffer and taken in account for
* refilling the buffer. This means that the input buffer
* must be large enough to hold a complete frame at the
* highest observable bit-rate (currently 448 kb/s). XXX=XXX
* Is 2016 bytes the size of the largest frame?
* (448000*(1152/32000))/8
*/
if (p_libmad_stream->next_frame!=NULL)
{
Remaining=p_libmad_stream->bufend-p_libmad_stream->next_frame;
memmove(p_mad_adec->buffer,p_libmad_stream->next_frame,Remaining);
ReadStart=p_mad_adec->buffer+Remaining;
ReadSize=(MAD_BUFFER_SIZE)-Remaining;
/* Store time stamp of next frame */
p_mad_adec->i_current_pts = p_mad_adec->i_next_pts;
CurrentPTS( &p_mad_adec->bit_stream, &p_mad_adec->i_next_pts, NULL );
}
else
{
ReadSize=(MAD_BUFFER_SIZE);
ReadStart=p_mad_adec->buffer;
Remaining=0;
p_mad_adec->i_next_pts = 0;
}
else
{
ReadSize=(MAD_BUFFER_SIZE);
ReadStart=p_mad_adec->buffer;
Remaining=0;
p_mad_adec->i_next_pts = 0;
CurrentPTS( &p_mad_adec->bit_stream, &p_mad_adec->i_current_pts, NULL );
}
}
//intf_ErrMsg( "mad_adec debug: buffer size remaining [%d] and readsize [%d] total [%d]",
// Remaining, ReadSize, ReadSize+Remaining);
/* Fill-in the buffer. If an error occurs print a message
* and leave the decoding loop. If the end of stream is
......@@ -132,13 +135,12 @@ enum mad_flow libmad_input(void *data, struct mad_stream *p_libmad_stream)
return MAD_FLOW_IGNORE;
}
/* Pipe the new buffer content to libmad's stream decoder facility.
* Libmad never copies the buffer, but just references it. So keep it in
* mad_adec_thread_t structure.
*/
mad_stream_buffer(p_libmad_stream,(unsigned char*) &p_mad_adec->buffer,
MAD_BUFFER_SIZE);
p_libmad_stream->error=0;
/* Pipe the new buffer content to libmad's stream decoder facility.
* Libmad never copies the buffer, but just references it. So keep it in
* mad_adec_thread_t structure.
*/
mad_stream_buffer(p_libmad_stream,(unsigned char*) &p_mad_adec->buffer,MAD_BUFFER_SIZE);
p_libmad_stream->error=0;
}
return MAD_FLOW_CONTINUE;
......@@ -157,7 +159,7 @@ enum mad_flow libmad_input(void *data, struct mad_stream *p_libmad_stream)
* intf_DbgMsg( "mad_adec: libmad_header bitrate %d", p_libmad_header->bitrate);
*
* p_mad_adec->p_aout_fifo->l_rate = p_libmad_header->samplerate;
* mad_timer_add(&p_mad_adec->libmad_timer,p_libmad_header->duration);
* mad_timer_add(&p_mad_adec->libmad_timer,p_libmad_header->duration);
*
* return MAD_FLOW_CONTINUE;
*}
......@@ -259,12 +261,12 @@ static __inline__ signed int audio_linear_dither(unsigned int bits, mad_fixed_t
/* scale */
return output >> scalebits;
}
#endif
#else
/*****************************************************************************
* s24_to_s16_pcm: Scale a 24 bit pcm sample to a 16 bit pcm sample.
*****************************************************************************/
static __inline__ mad_fixed_t s24_to_s16_pcm(mad_fixed_t sample)
static __inline__ mad_fixed_t (mad_fixed_t sample)
{
/* round */
sample += (1L << (MAD_F_FRACBITS - 16));
......@@ -278,6 +280,7 @@ static __inline__ mad_fixed_t s24_to_s16_pcm(mad_fixed_t sample)
/* quantize */
return sample >> (MAD_F_FRACBITS + 1 - 16);
}
#endif
/*****************************************************************************
* libmad_ouput: this function is called just after the frame is decoded
......@@ -294,10 +297,12 @@ enum mad_flow libmad_output(void *data, struct mad_header const *p_libmad_header
static struct audio_dither dither;
#endif
/* Creating the audio output fifo */
/* Creating the audio output fifo.
* Assume the samplerate and nr of channels from the first decoded frame is right for the entire audio track.
*/
if (p_mad_adec->p_aout_fifo==NULL)
{
p_mad_adec->p_aout_fifo = aout_CreateFifo(
p_mad_adec->p_aout_fifo = aout_CreateFifo(
AOUT_ADEC_STEREO_FIFO, /* fifo type */
p_libmad_pcm->channels, /* nr. of channels */
p_libmad_pcm->samplerate, /* frame rate in Hz ?*/
......@@ -312,28 +317,16 @@ enum mad_flow libmad_output(void *data, struct mad_header const *p_libmad_header
intf_ErrMsg("mad_adec debug: in libmad_output aout fifo created");
}
else
{
p_mad_adec->p_aout_fifo->l_rate = p_libmad_pcm->samplerate;
}
/* Some frames are nog quite right. Why ??? I do not know. Probably syncing and CRC errors ??
* Leaving those frames out futher removes the jitter in the sound and makes it more fluent.
* Still I am missing something, because it is not completely fluent.
*/
if ((p_mad_adec->libmad_decoder->sync->stream.error==MAD_ERROR_BADCRC) ||
(p_mad_adec->libmad_decoder->sync->stream.error==MAD_ERROR_BADBITRATE) ||
(p_mad_adec->libmad_decoder->sync->stream.error==MAD_ERROR_BADSCALEFACTOR)
) {
// intf_ErrMsg( "LIBMAD_OUTPUT: nr of channels [%d], samplerate in Hz [%d,%d], sample size [%d], error_code [%0x]",
// p_libmad_pcm->channels, p_libmad_pcm->samplerate, p_libmad_header->samplerate,
// p_libmad_pcm->length, p_mad_adec->libmad_decoder->sync->stream.error);
// PrintFrameInfo(&p_libmad_header);
return MAD_FLOW_IGNORE;
/* Set timestamp to synchronize audio and video decoder fifo's */
if (p_mad_adec->p_aout_fifo->l_rate != p_libmad_pcm->samplerate)
{
intf_ErrMsg( "mad_adec: libmad_output samplerate is changing from [%d] Hz to [%d] Hz, sample size [%d], error_code [%0x]",
p_mad_adec->p_aout_fifo->l_rate, p_libmad_pcm->samplerate,
p_libmad_pcm->length, p_mad_adec->libmad_decoder->sync->stream.error);
p_mad_adec->p_aout_fifo->l_rate = p_libmad_pcm->samplerate;
}
/* Set timestamp to synchronize audio and video decoder fifo's */
p_mad_adec->p_aout_fifo->l_rate = p_libmad_header->samplerate;
if( p_mad_adec->i_current_pts )
{
p_mad_adec->p_aout_fifo->date[p_mad_adec->p_aout_fifo->l_end_frame]
......@@ -437,7 +430,7 @@ enum mad_flow libmad_error(void *data, struct mad_stream *p_libmad_stream, struc
result = MAD_FLOW_CONTINUE;
break;
case MAD_ERROR_BADSAMPLERATE: /* reserved sample frequency value */
intf_ErrMsg("libmad error: reserved sample frequency value");
intf_ErrMsg("libmad error: reserved sample frequency value");
result = MAD_FLOW_CONTINUE;
break;
case MAD_ERROR_BADEMPHASIS: /* reserved emphasis value */
......@@ -498,8 +491,8 @@ enum mad_flow libmad_error(void *data, struct mad_stream *p_libmad_stream, struc
break;
}
//return (MAD_RECOVERABLE(p_libmad_stream->error)? result: MAD_FLOW_STOP);
return (MAD_FLOW_CONTINUE);
return (MAD_RECOVERABLE(p_libmad_stream->error)? result: MAD_FLOW_STOP);
//return (MAD_FLOW_CONTINUE);
}
/*****************************************************************************
......
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