* QCELP decoder
* @author Reynaldo H. Verdejo Pinochet
* @remark FFmpeg merging spearheaded by Kenan Gillet
+ * @remark Development mentored by Benjamin Larson
*/
#include <stddef.h>
#include "avcodec.h"
+#include "internal.h"
#include "bitstream.h"
-#include "qcelp.h"
#include "qcelpdata.h"
#include "celp_math.h"
#undef NDEBUG
#include <assert.h>
-typedef struct {
+typedef enum
+{
+ I_F_Q = -1, /*!< insufficient frame quality */
+ SILENCE,
+ RATE_OCTAVE,
+ RATE_QUARTER,
+ RATE_HALF,
+ RATE_FULL
+} qcelp_packet_rate;
+
+typedef struct
+{
GetBitContext gb;
qcelp_packet_rate bitrate;
- QCELPFrame frame; /*!< unpacked data frame */
- uint8_t erasure_count;
- uint8_t octave_count; /*!< count the consecutive RATE_OCTAVE frames */
- float prev_lspf[10];
- float predictor_lspf[10]; /*!< LSP predictor,
- only use for RATE_OCTAVE and I_F_Q */
- float formant_mem[170];
- float last_codebook_gain;
- int prev_g1[2];
- int prev_bitrate;
- float prev_pitch_gain[4];
- uint8_t prev_pitch_lag[4];
- uint16_t first16bits;
+ QCELPFrame frame; /*!< unpacked data frame */
+
+ uint8_t erasure_count;
+ uint8_t octave_count; /*!< count the consecutive RATE_OCTAVE frames */
+ float prev_lspf[10];
+ float predictor_lspf[10];/*!< LSP predictor for RATE_OCTAVE and I_F_Q */
+ float pitch_synthesis_filter_mem[303];
+ float pitch_pre_filter_mem[303];
+ float rnd_fir_filter_mem[180];
+ float formant_mem[170];
+ float last_codebook_gain;
+ int prev_g1[2];
+ int prev_bitrate;
+ float pitch_gain[4];
+ uint8_t pitch_lag[4];
+ uint16_t first16bits;
+ uint8_t warned_buf_mismatch_bitrate;
} QCELPContext;
+/**
+ * Reconstructs LPC coefficients from the line spectral pair frequencies.
+ *
+ * TIA/EIA/IS-733 2.4.3.3.5
+ */
+void ff_qcelp_lspf2lpc(const float *lspf, float *lpc);
+
static void weighted_vector_sumf(float *out, const float *in_a,
const float *in_b, float weight_coeff_a,
float weight_coeff_b, int length)
avctx->sample_fmt = SAMPLE_FMT_FLT;
- for (i = 0; i < 10; i++)
- q->prev_lspf[i] = (i + 1) / 11.;
+ for(i=0; i<10; i++)
+ q->prev_lspf[i] = (i+1)/11.;
return 0;
}
static int decode_lspf(QCELPContext *q, float *lspf)
{
int i;
- float tmp_lspf;
+ float tmp_lspf, smooth, erasure_coeff;
+ const float *predictors;
if(q->bitrate == RATE_OCTAVE || q->bitrate == I_F_Q)
{
- float smooth;
- const float *predictors = (q->prev_bitrate != RATE_OCTAVE &&
- q->prev_bitrate != I_F_Q ? q->prev_lspf
- : q->predictor_lspf);
+ predictors = (q->prev_bitrate != RATE_OCTAVE &&
+ q->prev_bitrate != I_F_Q ?
+ q->prev_lspf : q->predictor_lspf);
if(q->bitrate == RATE_OCTAVE)
{
smooth = (q->octave_count < 10 ? .875 : 0.1);
}else
{
- float erasure_coeff = QCELP_LSP_OCTAVE_PREDICTOR;
+ erasure_coeff = QCELP_LSP_OCTAVE_PREDICTOR;
assert(q->bitrate == I_F_Q);
int i, subframes_count, g1[16];
float slope;
- if (q->bitrate >= RATE_QUARTER) {
- switch (q->bitrate) {
+ if(q->bitrate >= RATE_QUARTER)
+ {
+ switch(q->bitrate)
+ {
case RATE_FULL: subframes_count = 16; break;
case RATE_HALF: subframes_count = 4; break;
default: subframes_count = 5;
}
- for (i = 0; i < subframes_count; i++) {
+ for(i=0; i<subframes_count; i++)
+ {
g1[i] = 4 * q->frame.cbgain[i];
- if (q->bitrate == RATE_FULL && !((i+1) & 3)) {
+ if(q->bitrate == RATE_FULL && !((i+1) & 3))
+ {
g1[i] += av_clip((g1[i-1] + g1[i-2] + g1[i-3]) / 3 - 6, 0, 32);
}
gain[i] = qcelp_g12ga[g1[i]];
- if (q->frame.cbsign[i]) {
+ if(q->frame.cbsign[i])
+ {
gain[i] = -gain[i];
q->frame.cindex[i] = (q->frame.cindex[i]-89) & 127;
}
q->prev_g1[1] = g1[i-1];
q->last_codebook_gain = qcelp_g12ga[g1[i-1]];
- if (q->bitrate == RATE_QUARTER) {
+ if(q->bitrate == RATE_QUARTER)
+ {
// Provide smoothing of the unvoiced excitation energy.
gain[7] = gain[4];
gain[6] = 0.4*gain[3] + 0.6*gain[4];
gain[2] = gain[1];
gain[1] = 0.6*gain[0] + 0.4*gain[1];
}
- } else {
- if (q->bitrate == RATE_OCTAVE) {
+ }else
+ {
+ if(q->bitrate == RATE_OCTAVE)
+ {
g1[0] = 2 * q->frame.cbgain[0]
+ av_clip((q->prev_g1[0] + q->prev_g1[1]) / 2 - 5, 0, 54);
subframes_count = 8;
- } else {
+ }else
+ {
assert(q->bitrate == I_F_Q);
g1[0] = q->prev_g1[1];
- switch (q->erasure_count) {
- case 1 : break;
- case 2 : g1[0] -= 1; break;
- case 3 : g1[0] -= 2; break;
- default: g1[0] -= 6;
+ switch(q->erasure_count)
+ {
+ case 1 : break;
+ case 2 : g1[0] -= 1; break;
+ case 3 : g1[0] -= 2; break;
+ default: g1[0] -= 6;
}
- if (g1[0] < 0)
+ if(g1[0] < 0)
g1[0] = 0;
subframes_count = 4;
}
// This interpolation is done to produce smoother background noise.
slope = 0.5*(qcelp_g12ga[g1[0]] - q->last_codebook_gain) / subframes_count;
- for (i = 1; i <= subframes_count; i++)
+ for(i=1; i<=subframes_count; i++)
gain[i-1] = q->last_codebook_gain + slope * i;
- q->last_codebook_gain = gain[i-2];
+ q->last_codebook_gain = gain[i-2];
q->prev_g1[0] = q->prev_g1[1];
q->prev_g1[1] = g1[0];
}
*/
static int codebook_sanity_check_for_rate_quarter(const uint8_t *cbgain)
{
- int i, prev_diff=0;
+ int i, diff, prev_diff=0;
for(i=1; i<5; i++)
{
- int diff = cbgain[i] - cbgain[i-1];
+ diff = cbgain[i] - cbgain[i-1];
if(FFABS(diff) > 10)
return -1;
else if(FFABS(diff - prev_diff) > 12)
* @param gain array holding the 4 pitch subframe gain values
* @param cdn_vector array for the generated scaled codebook vector
*/
-static void compute_svector(const QCELPContext *q, const float *gain,
+static void compute_svector(QCELPContext *q, const float *gain,
float *cdn_vector)
{
int i, j, k;
scalefactor = sqrt(ff_dot_productf(v_ref + j, v_ref + j, 40)
/ scalefactor);
else
- av_log_missing_feature(NULL, "Zero energy for gain control", 1);
+ ff_log_missing_feature(NULL, "Zero energy for gain control", 1);
for(len=j+40; j<len; j++)
v_out[j] = scalefactor * v_in[j];
}
return memory + 143;
}
+/**
+ * Apply pitch synthesis filter and pitch prefilter to the scaled codebook vector.
+ * TIA/EIA/IS-733 2.4.5.2
+ *
+ * @param q the context
+ * @param cdn_vector the scaled codebook vector
+ */
+static void apply_pitch_filters(QCELPContext *q, float *cdn_vector)
+{
+ int i;
+ const float *v_synthesis_filtered, *v_pre_filtered;
+
+ if(q->bitrate >= RATE_HALF ||
+ (q->bitrate == I_F_Q && (q->prev_bitrate >= RATE_HALF)))
+ {
+
+ if(q->bitrate >= RATE_HALF)
+ {
+
+ // Compute gain & lag for the whole frame.
+ for(i=0; i<4; i++)
+ {
+ q->pitch_gain[i] = q->frame.plag[i] ? (q->frame.pgain[i] + 1) * 0.25 : 0.0;
+
+ q->pitch_lag[i] = q->frame.plag[i] + 16;
+ }
+ }else
+ {
+ float max_pitch_gain;
+
+ if (q->erasure_count < 3)
+ max_pitch_gain = 0.9 - 0.3 * (q->erasure_count - 1);
+ else
+ max_pitch_gain = 0.0;
+ for(i=0; i<4; i++)
+ q->pitch_gain[i] = FFMIN(q->pitch_gain[i], max_pitch_gain);
+
+ memset(q->frame.pfrac, 0, sizeof(q->frame.pfrac));
+ }
+
+ // pitch synthesis filter
+ v_synthesis_filtered = do_pitchfilter(q->pitch_synthesis_filter_mem,
+ cdn_vector, q->pitch_gain,
+ q->pitch_lag, q->frame.pfrac);
+
+ // pitch prefilter update
+ for(i=0; i<4; i++)
+ q->pitch_gain[i] = 0.5 * FFMIN(q->pitch_gain[i], 1.0);
+
+ v_pre_filtered = do_pitchfilter(q->pitch_pre_filter_mem,
+ v_synthesis_filtered,
+ q->pitch_gain, q->pitch_lag,
+ q->frame.pfrac);
+
+ apply_gain_ctrl(cdn_vector, v_synthesis_filtered, v_pre_filtered);
+ }else
+ {
+ memcpy(q->pitch_synthesis_filter_mem, cdn_vector + 17,
+ 143 * sizeof(float));
+ memcpy(q->pitch_pre_filter_mem, cdn_vector + 17, 143 * sizeof(float));
+ memset(q->pitch_gain, 0, sizeof(q->pitch_gain));
+ memset(q->pitch_lag, 0, sizeof(q->pitch_lag));
+ }
+}
+
/**
* Interpolates LSP frequencies and computes LPC coefficients
* for a given bitrate & pitch subframe.
{
weighted_vector_sumf(interpolated_lspf, curr_lspf, q->prev_lspf,
weight, 1.0 - weight, 10);
- qcelp_lspf2lpc(interpolated_lspf, lpc);
- }else if(q->bitrate >= RATE_QUARTER || (q->bitrate == I_F_Q && !subframe_num))
- qcelp_lspf2lpc(curr_lspf, lpc);
+ ff_qcelp_lspf2lpc(interpolated_lspf, lpc);
+ }else if(q->bitrate >= RATE_QUARTER ||
+ (q->bitrate == I_F_Q && !subframe_num))
+ ff_qcelp_lspf2lpc(curr_lspf, lpc);
}
-static int buf_size2bitrate(const int buf_size)
+static qcelp_packet_rate buf_size2bitrate(const int buf_size)
{
switch(buf_size)
{
- case 35:
- return RATE_FULL;
- case 17:
- return RATE_HALF;
- case 8:
- return RATE_QUARTER;
- case 4:
- return RATE_OCTAVE;
- case 1:
- return SILENCE;
+ case 35: return RATE_FULL;
+ case 17: return RATE_HALF;
+ case 8: return RATE_QUARTER;
+ case 4: return RATE_OCTAVE;
+ case 1: return SILENCE;
}
- return -1;
+ return I_F_Q;
+}
+
+/**
+ * Determine the bitrate from the frame size and/or the first byte of the frame.
+ *
+ * @param avctx the AV codec context
+ * @param buf_size length of the buffer
+ * @param buf the bufffer
+ *
+ * @return the bitrate on success,
+ * I_F_Q if the bitrate cannot be satisfactorily determined
+ *
+ * TIA/EIA/IS-733 2.4.8.7.1
+ */
+static int determine_bitrate(AVCodecContext *avctx, const int buf_size,
+ const uint8_t **buf)
+{
+ qcelp_packet_rate bitrate;
+
+ if((bitrate = buf_size2bitrate(buf_size)) >= 0)
+ {
+ if(bitrate > **buf)
+ {
+ QCELPContext *q = avctx->priv_data;
+ if (!q->warned_buf_mismatch_bitrate)
+ {
+ av_log(avctx, AV_LOG_WARNING,
+ "Claimed bitrate and buffer size mismatch.\n");
+ q->warned_buf_mismatch_bitrate = 1;
+ }
+ bitrate = **buf;
+ }else if(bitrate < **buf)
+ {
+ av_log(avctx, AV_LOG_ERROR,
+ "Buffer is too small for the claimed bitrate.\n");
+ return I_F_Q;
+ }
+ (*buf)++;
+ }else if((bitrate = buf_size2bitrate(buf_size + 1)) >= 0)
+ {
+ av_log(avctx, AV_LOG_WARNING,
+ "Bitrate byte is missing, guessing the bitrate from packet size.\n");
+ }else
+ return I_F_Q;
+
+ if(bitrate == SILENCE)
+ {
+ // FIXME: the decoder should not handle SILENCE frames as I_F_Q frames
+ ff_log_missing_feature(avctx, "Blank frame", 1);
+ bitrate = I_F_Q;
+ }
+ return bitrate;
}
static void warn_insufficient_frame_quality(AVCodecContext *avctx,
message);
}
-static int qcelp_decode_frame(AVCodecContext *avctx,
- void *data,
- int *data_size,
- uint8_t *buf,
- const int buf_size) {
- QCELPContext *q = avctx->priv_data;
- float *outbuffer = data;
- int i;
- float quantized_lspf[10], lpc[10];
- float gain[16];
- float *formant_mem;
-
- if ((q->bitrate = determine_bitrate(avctx, buf_size, &buf)) == I_F_Q) {
+static int qcelp_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
+ const uint8_t *buf, int buf_size)
+{
+ QCELPContext *q = avctx->priv_data;
+ float *outbuffer = data;
+ int i;
+ float quantized_lspf[10], lpc[10];
+ float gain[16];
+ float *formant_mem;
+
+ if((q->bitrate = determine_bitrate(avctx, buf_size, &buf)) == I_F_Q)
+ {
warn_insufficient_frame_quality(avctx, "bitrate cannot be determined.");
goto erasure;
}
- if (q->bitrate == RATE_OCTAVE &&
- (q->first16bits = AV_RB16(buf)) == 0xFFFF) {
+ if(q->bitrate == RATE_OCTAVE &&
+ (q->first16bits = AV_RB16(buf)) == 0xFFFF)
+ {
warn_insufficient_frame_quality(avctx, "Bitrate is 1/8 and first 16 bits are on.");
goto erasure;
}
- if (q->bitrate > SILENCE) {
+ if(q->bitrate > SILENCE)
+ {
const QCELPBitmap *bitmaps = qcelp_unpacking_bitmaps_per_rate[q->bitrate];
const QCELPBitmap *bitmaps_end = qcelp_unpacking_bitmaps_per_rate[q->bitrate]
+ qcelp_unpacking_bitmaps_lengths[q->bitrate];
memset(&q->frame, 0, sizeof(QCELPFrame));
- for (; bitmaps < bitmaps_end; bitmaps++)
+ for(; bitmaps < bitmaps_end; bitmaps++)
unpacked_data[bitmaps->index] |= get_bits(&q->gb, bitmaps->bitlen) << bitmaps->bitpos;
// Check for erasures/blanks on rates 1, 1/4 and 1/8.
- if (q->frame.reserved) {
+ if(q->frame.reserved)
+ {
warn_insufficient_frame_quality(avctx, "Wrong data in reserved frame area.");
goto erasure;
}
- if (q->bitrate == RATE_QUARTER && codebook_sanity_check_for_rate_quarter(q->frame.cbgain)) {
+ if(q->bitrate == RATE_QUARTER &&
+ codebook_sanity_check_for_rate_quarter(q->frame.cbgain))
+ {
warn_insufficient_frame_quality(avctx, "Codebook gain sanity check failed.");
goto erasure;
}
- if (q->bitrate >= RATE_HALF) {
- for (i = 0; i < 4; i++) {
- if (q->frame.pfrac[i] && q->frame.plag[i] >= 124) {
+ if(q->bitrate >= RATE_HALF)
+ {
+ for(i=0; i<4; i++)
+ {
+ if(q->frame.pfrac[i] && q->frame.plag[i] >= 124)
+ {
warn_insufficient_frame_quality(avctx, "Cannot initialize pitch filter.");
goto erasure;
}
decode_gain_and_index(q, gain);
compute_svector(q, gain, outbuffer);
- if (decode_lspf(q, quantized_lspf) < 0) {
+ if(decode_lspf(q, quantized_lspf) < 0)
+ {
warn_insufficient_frame_quality(avctx, "Badly received packets in frame.");
goto erasure;
}
apply_pitch_filters(q, outbuffer);
- if (q->bitrate == I_F_Q) {
+ if(q->bitrate == I_F_Q)
+ {
erasure:
q->bitrate = I_F_Q;
q->erasure_count++;
compute_svector(q, gain, outbuffer);
decode_lspf(q, quantized_lspf);
apply_pitch_filters(q, outbuffer);
- } else
+ }else
q->erasure_count = 0;
formant_mem = q->formant_mem + 10;
- for (i = 0; i < 4; i++) {
+ for(i=0; i<4; i++)
+ {
interpolate_lpc(q, quantized_lspf, lpc, i);
- ff_celp_lp_synthesis_filterf(formant_mem, lpc, outbuffer + i * 40, 40, 10);
+ ff_celp_lp_synthesis_filterf(formant_mem, lpc, outbuffer + i * 40, 40,
+ 10);
formant_mem += 40;
}
memcpy(q->formant_mem, q->formant_mem + 160, 10 * sizeof(float));
// TIA/EIA/IS-733 2.4.8.6
formant_mem = q->formant_mem + 10;
- for (i = 0; i < 160; i++)
- *outbuffer++ = av_clipf(*formant_mem++, QCELP_CLIP_LOWER_BOUND, QCELP_CLIP_UPPER_BOUND);
+ for(i=0; i<160; i++)
+ *outbuffer++ = av_clipf(*formant_mem++, QCELP_CLIP_LOWER_BOUND,
+ QCELP_CLIP_UPPER_BOUND);
memcpy(q->prev_lspf, quantized_lspf, sizeof(q->prev_lspf));
q->prev_bitrate = q->bitrate;