---
I don't have samples for it so it's rather theoretical.
---
libavcodec/imc.c | 151 ++++++++++++++++++++++++++++++++++++------------------
1 file changed, 102 insertions(+), 49 deletions(-)
diff --git a/libavcodec/imc.c b/libavcodec/imc.c
index e3f5e15..a451bc8 100644
--- a/libavcodec/imc.c
+++ b/libavcodec/imc.c
@@ -65,7 +65,7 @@ typedef struct IMCChannel {
int bandWidthT[BANDS]; ///< codewords per band
int bitsBandT[BANDS]; ///< how many bits per codeword in band
int CWlengthT[COEFFS]; ///< how many bits in each codeword
- int levlCoeffBuf[BANDS];
+ int levlCoeffBuf[BANDS + 1];
int bandFlagsBuf[BANDS]; ///< flags for each band
int sumLenArr[BANDS]; ///< bits for all coeffs in band
int skipFlagRaw[BANDS]; ///< skip flags are stored in raw form or not
@@ -336,6 +336,17 @@ static void imc_read_level_coeffs(IMCContext *q, int
stream_format_code,
}
}
+static void imc_read_level_coeffs_raw(IMCContext *q, int stream_format_code,
+ int *levlCoeffs)
+{
+ int i;
+
+ levlCoeffs[0] = get_bits(&q->gb, 5);
+ levlCoeffs[1] = get_bits(&q->gb, 7);
+ for (i = 1; i < BANDS; i++)
+ levlCoeffs[i + 1] = get_bits(&q->gb, 4);
+}
+
static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,
float *flcoeffs1, float *flcoeffs2)
{
@@ -390,6 +401,28 @@ static void imc_decode_level_coefficients2(IMCContext *q,
int *levlCoeffBuf,
}
}
+static void imc_decode_level_coefficients_raw(IMCContext *q, int *levlCoeffBuf,
+ float *flcoeffs1, float
*flcoeffs2)
+{
+ int i, level, pos;
+ float tmp, tmp2;
+
+ pos = levlCoeffBuf[0];
+ flcoeffs1[pos] = 20000.0 / pow (2, levlCoeffBuf[1] * 0.18945); // 0.18945
= log2(10) * 0.05703125
+ flcoeffs2[pos] = log2f(flcoeffs1[0]);
+ tmp = flcoeffs1[pos];
+ tmp2 = flcoeffs2[pos];
+
+ levlCoeffBuf += 2;
+ for (i = 0; i < BANDS; i++) {
+ if (i == pos)
+ continue;
+ level = *levlCoeffBuf++;
+ flcoeffs1[i] = tmp * powf(10.0, -level * 0.4375); //todo tab
+ flcoeffs2[i] = tmp2 - 1.4533435415 * level; // 1.4533435415 = log2(10)
* 0.4375
+ }
+}
+
/**
* Perform bit allocation depending on bits available
*/
@@ -781,11 +814,6 @@ static int imc_decode_block(AVCodecContext *avctx,
IMCContext *q, int ch)
}
stream_format_code = get_bits(&q->gb, 3);
- if (stream_format_code & 1) {
- avpriv_request_sample(avctx, "Stream format %X", stream_format_code);
- return AVERROR_PATCHWELCOME;
- }
-
if (stream_format_code & 0x04)
chctx->decoder_reset = 1;
@@ -798,9 +826,15 @@ static int imc_decode_block(AVCodecContext *avctx,
IMCContext *q, int ch)
}
flag = get_bits1(&q->gb);
- imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);
+ if (stream_format_code & 0x1)
+ imc_read_level_coeffs_raw(q, stream_format_code, chctx->levlCoeffBuf);
+ else
+ imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);
- if (stream_format_code & 0x4)
+ if (stream_format_code & 0x1)
+ imc_decode_level_coefficients_raw(q, chctx->levlCoeffBuf,
+ chctx->flcoeffs1, chctx->flcoeffs2);
+ else if (stream_format_code & 0x4)
imc_decode_level_coefficients(q, chctx->levlCoeffBuf,
chctx->flcoeffs1, chctx->flcoeffs2);
else
@@ -810,20 +844,31 @@ static int imc_decode_block(AVCodecContext *avctx,
IMCContext *q, int ch)
memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));
counter = 0;
- for (i = 0; i < BANDS; i++) {
- if (chctx->levlCoeffBuf[i] == 16) {
- chctx->bandWidthT[i] = 0;
- counter++;
- } else
+ if (stream_format_code & 0x1) {
+ for (i = 0; i < BANDS; i++) {
chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
- }
- memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
- for (i = 0; i < BANDS - 1; i++) {
- if (chctx->bandWidthT[i])
- chctx->bandFlagsBuf[i] = get_bits1(&q->gb);
- }
+ chctx->bandFlagsBuf[i] = 0;
+ chctx->flcoeffs3[i] = chctx->flcoeffs2[i] * 2;
+ chctx->flcoeffs5[i] = 1.0;
+ }
+ } else {
+ for (i = 0; i < BANDS; i++) {
+ if (chctx->levlCoeffBuf[i] == 16) {
+ chctx->bandWidthT[i] = 0;
+ counter++;
+ } else
+ chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
+ }
- imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2,
chctx->bandWidthT, chctx->flcoeffs3, chctx->flcoeffs5);
+ memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
+ for (i = 0; i < BANDS - 1; i++)
+ if (chctx->bandWidthT[i])
+ chctx->bandFlagsBuf[i] = get_bits1(&q->gb);
+
+ imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2,
+ chctx->bandWidthT, chctx->flcoeffs3,
+ chctx->flcoeffs5);
+ }
bitscount = 0;
/* first 4 bands will be assigned 5 bits per coefficient */
@@ -835,7 +880,10 @@ static int imc_decode_block(AVCodecContext *avctx,
IMCContext *q, int ch)
chctx->CWlengthT[1] = 5;
chctx->CWlengthT[2] = 5;
for (i = 1; i < 4; i++) {
- bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;
+ if (stream_format_code & 0x1)
+ bits = 5;
+ else
+ bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;
chctx->bitsBandT[i] = bits;
for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
chctx->CWlengthT[j] = bits;
@@ -857,43 +905,48 @@ static int imc_decode_block(AVCodecContext *avctx,
IMCContext *q, int ch)
return ret;
}
- for (i = 0; i < BANDS; i++) {
- chctx->sumLenArr[i] = 0;
- chctx->skipFlagRaw[i] = 0;
- for (j = band_tab[i]; j < band_tab[i + 1]; j++)
- chctx->sumLenArr[i] += chctx->CWlengthT[j];
- if (chctx->bandFlagsBuf[i])
- if ((((band_tab[i + 1] - band_tab[i]) * 1.5) >
chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
- chctx->skipFlagRaw[i] = 1;
- }
+ if (stream_format_code & 1) {
+ for (i = 0; i < BANDS; i++)
+ chctx->skipFlags[i] = 0;
+ } else {
+ for (i = 0; i < BANDS; i++) {
+ chctx->sumLenArr[i] = 0;
+ chctx->skipFlagRaw[i] = 0;
+ for (j = band_tab[i]; j < band_tab[i + 1]; j++)
+ chctx->sumLenArr[i] += chctx->CWlengthT[j];
+ if (chctx->bandFlagsBuf[i])
+ if ((((band_tab[i + 1] - band_tab[i]) * 1.5) >
chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
+ chctx->skipFlagRaw[i] = 1;
+ }
- imc_get_skip_coeff(q, chctx);
+ imc_get_skip_coeff(q, chctx);
- for (i = 0; i < BANDS; i++) {
- chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
- /* band has flag set and at least one coded coefficient */
- if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) !=
chctx->skipFlagCount[i]) {
- chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]]
/
- q->sqrt_tab[(band_tab[i + 1] - band_tab[i]
- chctx->skipFlagCount[i])];
+ for (i = 0; i < BANDS; i++) {
+ chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
+ /* band has flag set and at least one coded coefficient */
+ if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) !=
chctx->skipFlagCount[i]) {
+ chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] -
band_tab[i]] /
+ q->sqrt_tab[(band_tab[i + 1] -
band_tab[i] - chctx->skipFlagCount[i])];
+ }
}
- }
- /* calculate bits left, bits needed and adjust bit allocation */
- bits = summer = 0;
+ /* calculate bits left, bits needed and adjust bit allocation */
+ bits = summer = 0;
- for (i = 0; i < BANDS; i++) {
- if (chctx->bandFlagsBuf[i]) {
- for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
- if (chctx->skipFlags[j]) {
- summer += chctx->CWlengthT[j];
- chctx->CWlengthT[j] = 0;
+ for (i = 0; i < BANDS; i++) {
+ if (chctx->bandFlagsBuf[i]) {
+ for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
+ if (chctx->skipFlags[j]) {
+ summer += chctx->CWlengthT[j];
+ chctx->CWlengthT[j] = 0;
+ }
}
+ bits += chctx->skipFlagBits[i];
+ summer -= chctx->skipFlagBits[i];
}
- bits += chctx->skipFlagBits[i];
- summer -= chctx->skipFlagBits[i];
}
+ imc_adjust_bit_allocation(q, chctx, summer);
}
- imc_adjust_bit_allocation(q, chctx, summer);
for (i = 0; i < BANDS; i++) {
chctx->sumLenArr[i] = 0;
--
1.7.9.5
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