adpcmdec: checkpoint for incomplete IMA ADPCM support.

This commit is contained in:
Michael Smith 2009-07-23 11:59:39 -07:00
parent 2a7ee0716f
commit e90934dab3

View file

@ -19,7 +19,7 @@
* Boston, MA 02111-1307, USA.
*/
/* Based on MS-ADPCM decoder in libsndfile,
/* Based on ADPCM decoders in libsndfile,
Copyright (C) 1999-2002 Erik de Castro Lopo <erikd@zip.com.au
*/
@ -40,19 +40,19 @@
GST_DEBUG_CATEGORY_STATIC (adpcmdec_debug);
static const GstElementDetails adpcmdec_details =
GST_ELEMENT_DETAILS ("MS-ADPCM decoder",
GST_ELEMENT_DETAILS ("ADPCM decoder",
"Codec/Decoder/Audio",
"Decode MS AD-PCM audio",
"Decode MS and IMA ADPCM audio",
"Pioneers of the Inevitable <songbird@songbirdnest.com");
static GstStaticPadTemplate adpcmdec_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/x-adpcm, "
"layout=(string)microsoft, "
"block_align = (int) [64, 8096], "
"rate = (int)[ 1, MAX ], " "channels = (int)[1,2]")
" layout=(string){microsoft, dvi}, "
" block_align = (int) [64, 8096], "
" rate = (int)[ 1, MAX ], " "channels = (int)[1,2];")
);
static GstStaticPadTemplate adpcmdec_src_template =
@ -67,6 +67,12 @@ GST_STATIC_PAD_TEMPLATE ("src",
"channels = (int) [1,2], " "rate = (int)[1, MAX]")
);
enum adpcm_layout
{
LAYOUT_ADPCM_MICROSOFT,
LAYOUT_ADPCM_DVI
};
typedef struct _ADPCMDecClass
{
GstElementClass parent_class;
@ -81,6 +87,7 @@ typedef struct _ADPCMDec
GstCaps *output_caps;
enum adpcm_layout layout;
int rate;
int channels;
int blocksize;
@ -139,6 +146,18 @@ adpcmdec_sink_setcaps (GstPad * pad, GstCaps * caps)
{
ADPCMDec *dec = (ADPCMDec *) gst_pad_get_parent (pad);
GstStructure *structure = gst_caps_get_structure (caps, 0);
const gchar *layout;
layout = gst_structure_get_string (structure, "layout");
if (!layout)
return FALSE;
if (g_str_equal (layout, "microsoft"))
dec->layout = LAYOUT_ADPCM_MICROSOFT;
else if (g_str_equal (layout, "dvi"))
dec->layout = LAYOUT_ADPCM_DVI;
else
return FALSE;
if (!gst_structure_get_int (structure, "block_align", &dec->blocksize))
return FALSE;
@ -282,6 +301,92 @@ adpcmdec_decode_ms_block (ADPCMDec * dec, int n_samples, guint8 * data,
return TRUE;
}
static int ima_indx_adjust[16] = { -1, -1, -1, -1, /* +0 - +3, decrease the step size */
2, 4, 6, 8, /* +4 - +7, increase the step size */
-1, -1, -1, -1, /* -0 - -3, decrease the step size */
2, 4, 6, 8, /* -4 - -7, increase the step size */
};
static int ima_step_size[89] = {
7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230,
253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327,
3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442,
11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794,
32767
};
/* Decode a single block of data from 'data', storing 'n_samples' decoded 16 bit
samples in 'samples'.
All buffer lengths have been verified by the caller
*/
static gboolean
adpcmdec_decode_ima_block (ADPCMDec * dec, int n_samples, guint8 * data,
gint16 * samples)
{
gint16 stepindex[2];
int channel;
int idx; /* Current byte offset in 'data' */
int i; /* Current sample */
for (channel = 0; channel < dec->channels; channel++) {
samples[channel] = read_sample (data + channel * 4);
stepindex[channel] = CLAMP (data[channel * 4 + 2], 0, 88);
if (data[channel * 4 + 3] != 0) {
GST_WARNING_OBJECT (dec, "Synchronisation error");
return FALSE;
}
}
i = dec->channels;
idx = 4 * dec->channels;
GST_DEBUG ("Decoding %d samples", n_samples);
for (; i < n_samples; i++) {
int chan = i % dec->channels;
int bytecode;
int step;
int val;
int difference;
#if 1
if (i % 2 == 0) {
bytecode = (data[idx] >> 4) & 0x0F;
} else {
bytecode = data[idx] & 0x0F;
idx++;
}
#endif
step = ima_step_size[stepindex[chan]];
#if 1
difference = (2 * (bytecode & 0x7) * step + step) / 8;
if (bytecode & 8)
difference = -difference;
#else
val = step >> 3;
if (bytecode & 4)
val += step;
if (bytecode & 2)
val += step >> 1;
if (bytecode & 1)
val += step >> 2;
if (bytecode & 8)
val = -val;
difference = val;
#endif
val = (int) samples[i - dec->channels] + difference;
samples[i] = CLAMP (val, G_MININT16, G_MAXINT16);
stepindex[channel] = CLAMP (stepindex[channel] + ima_indx_adjust[bytecode],
0, 88);
}
return TRUE;
}
static GstFlowReturn
adpcmdec_chain (GstPad * pad, GstBuffer * buf)
{
@ -306,15 +411,30 @@ adpcmdec_chain (GstPad * pad, GstBuffer * buf)
databuf = gst_adapter_take_buffer (dec->adapter, dec->blocksize);
data = GST_BUFFER_DATA (databuf);
/* Each block has a 3 byte header per channel, plus 4 bytes per channel to
give two initial sample values per channel. Then the remainder gives
two samples per byte */
samples = (dec->blocksize - 7 * dec->channels) * 2 + 2 * dec->channels;
outsize = 2 * samples;
outbuf = gst_buffer_new_and_alloc (outsize);
if (dec->layout == LAYOUT_ADPCM_MICROSOFT) {
/* Each block has a 3 byte header per channel, plus 4 bytes per channel to
give two initial sample values per channel. Then the remainder gives
two samples per byte */
samples = (dec->blocksize - 7 * dec->channels) * 2 + 2 * dec->channels;
outsize = 2 * samples;
outbuf = gst_buffer_new_and_alloc (outsize);
res = adpcmdec_decode_ms_block (dec, samples, data,
(gint16 *) (GST_BUFFER_DATA (outbuf)));
res = adpcmdec_decode_ms_block (dec, samples, data,
(gint16 *) (GST_BUFFER_DATA (outbuf)));
} else if (dec->layout == LAYOUT_ADPCM_DVI) {
/* Each block has a 4 byte header per channel, include an initial sample.
Then the remainder gives two samples per byte */
samples = (dec->blocksize - 4 * dec->channels) * 2 + dec->channels;
outsize = 2 * samples;
outbuf = gst_buffer_new_and_alloc (outsize);
res = adpcmdec_decode_ima_block (dec, samples, data,
(gint16 *) (GST_BUFFER_DATA (outbuf)));
} else {
GST_WARNING_OBJECT (dec, "Unknown layout");
ret = GST_FLOW_ERROR;
goto done;
}
/* Done with input data, free it */
gst_buffer_unref (databuf);
@ -440,7 +560,7 @@ static gboolean
plugin_init (GstPlugin * plugin)
{
GST_DEBUG_CATEGORY_INIT (adpcmdec_debug, "adpcmdec", 0, "ADPCM Decoders");
if (!gst_element_register (plugin, "msadpcmdec", GST_RANK_PRIMARY,
if (!gst_element_register (plugin, "adpcmdec", GST_RANK_PRIMARY,
GST_TYPE_ADPCM_DEC)) {
return FALSE;
}