[SCM] libav/experimental: Add a G.722 encoder

siretart at users.alioth.debian.org siretart at users.alioth.debian.org
Sun Jun 30 17:16:03 UTC 2013


The following commit has been merged in the experimental branch:
commit 21e681ba57735bca225f1f903c7e93ffdb0f86ba
Author: Martin Storsjö <martin at martin.st>
Date:   Thu Sep 23 21:33:29 2010 +0000

    Add a G.722 encoder
    
    Originally committed as revision 25164 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/Changelog b/Changelog
index 503ac43..682d399 100644
--- a/Changelog
+++ b/Changelog
@@ -33,7 +33,7 @@ version <next>:
 - Apple HTTP Live Streaming demuxer
 - a64 codec
 - MMS-HTTP support
-- G.722 ADPCM audio decoder
+- G.722 ADPCM audio encoder/decoder
 - R10k video decoder
 - ocv_smooth filter
 
diff --git a/doc/general.texi b/doc/general.texi
index 9a3200f..b9953cc 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -536,7 +536,7 @@ following image formats are supported:
 @item ADPCM Electronic Arts R2  @tab     @tab  X
 @item ADPCM Electronic Arts R3  @tab     @tab  X
 @item ADPCM Electronic Arts XAS @tab     @tab  X
- at item ADPCM G.722            @tab     @tab  X
+ at item ADPCM G.722            @tab  X  @tab  X
 @item ADPCM G.726            @tab  X  @tab  X
 @item ADPCM IMA AMV          @tab     @tab  X
     @tab Used in AMV files
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index a9bb529..83aece2 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -477,6 +477,7 @@ OBJS-$(CONFIG_ADPCM_EA_R2_DECODER)        += adpcm.o
 OBJS-$(CONFIG_ADPCM_EA_R3_DECODER)        += adpcm.o
 OBJS-$(CONFIG_ADPCM_EA_XAS_DECODER)       += adpcm.o
 OBJS-$(CONFIG_ADPCM_G722_DECODER)         += g722.o
+OBJS-$(CONFIG_ADPCM_G722_ENCODER)         += g722.o
 OBJS-$(CONFIG_ADPCM_G726_DECODER)         += g726.o
 OBJS-$(CONFIG_ADPCM_G726_ENCODER)         += g726.o
 OBJS-$(CONFIG_ADPCM_IMA_AMV_DECODER)      += adpcm.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index bc8831f..d499f25 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -318,7 +318,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER (ADPCM_EA_R2, adpcm_ea_r2);
     REGISTER_DECODER (ADPCM_EA_R3, adpcm_ea_r3);
     REGISTER_DECODER (ADPCM_EA_XAS, adpcm_ea_xas);
-    REGISTER_DECODER (ADPCM_G722, adpcm_g722);
+    REGISTER_ENCDEC  (ADPCM_G722, adpcm_g722);
     REGISTER_ENCDEC  (ADPCM_G726, adpcm_g726);
     REGISTER_DECODER (ADPCM_IMA_AMV, adpcm_ima_amv);
     REGISTER_DECODER (ADPCM_IMA_DK3, adpcm_ima_dk3);
diff --git a/libavcodec/g722.c b/libavcodec/g722.c
index 8707d16..51a0f39 100644
--- a/libavcodec/g722.c
+++ b/libavcodec/g722.c
@@ -1,5 +1,5 @@
 /*
- * G.722 ADPCM audio decoder
+ * G.722 ADPCM audio encoder/decoder
  *
  * Copyright (c) CMU 1993 Computer Science, Speech Group
  *                        Chengxiang Lu and Alex Hauptmann
@@ -219,6 +219,7 @@ static av_cold int g722_init(AVCodecContext * avctx)
     return 0;
 }
 
+#if CONFIG_ADPCM_G722_DECODER
 static const int16_t low_inv_quant5[32] = {
      -35,   -35, -2919, -2195, -1765, -1458, -1219, -1023,
     -858,  -714,  -587,  -473,  -370,  -276,  -190,  -110,
@@ -301,4 +302,84 @@ AVCodec adpcm_g722_decoder = {
     .long_name      = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
     .max_lowres     = 1,
 };
+#endif
+
+#if CONFIG_ADPCM_G722_ENCODER
+static const int16_t low_quant[33] = {
+      35,   72,  110,  150,  190,  233,  276,  323,
+     370,  422,  473,  530,  587,  650,  714,  786,
+     858,  940, 1023, 1121, 1219, 1339, 1458, 1612,
+    1765, 1980, 2195, 2557, 2919
+};
+
+static inline void filter_samples(G722Context *c, const int16_t *samples,
+                                  int *xlow, int *xhigh)
+{
+    int xout1, xout2;
+    c->prev_samples[c->prev_samples_pos++] = samples[0];
+    c->prev_samples[c->prev_samples_pos++] = samples[1];
+    apply_qmf(c->prev_samples + c->prev_samples_pos - 24, &xout1, &xout2);
+    *xlow  = xout1 + xout2 >> 13;
+    *xhigh = xout1 - xout2 >> 13;
+    if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) {
+        memmove(c->prev_samples,
+                c->prev_samples + c->prev_samples_pos - 22,
+                22 * sizeof(c->prev_samples[0]));
+        c->prev_samples_pos = 22;
+    }
+}
+
+static inline int encode_high(const struct G722Band *state, int xhigh)
+{
+    int diff = av_clip_int16(xhigh - state->s_predictor);
+    int pred = 141 * state->scale_factor >> 8;
+           /* = diff >= 0 ? (diff < pred) + 2 : diff >= -pred */
+    return ((diff ^ (diff >> (sizeof(diff)*8-1))) < pred) + 2*(diff >= 0);
+}
+
+static inline int encode_low(const struct G722Band* state, int xlow)
+{
+    int diff  = av_clip_int16(xlow - state->s_predictor);
+           /* = diff >= 0 ? diff : -(diff + 1) */
+    int limit = diff ^ (diff >> (sizeof(diff)*8-1));
+    int i = 0;
+    limit = limit + 1 << 10;
+    if (limit > low_quant[8] * state->scale_factor)
+        i = 9;
+    while (i < 29 && limit > low_quant[i] * state->scale_factor)
+        i++;
+    return (diff < 0 ? (i < 2 ? 63 : 33) : 61) - i;
+}
+
+static int g722_encode_frame(AVCodecContext *avctx,
+                             uint8_t *dst, int buf_size, void *data)
+{
+    G722Context *c = avctx->priv_data;
+    const int16_t *samples = data;
+    int i;
+
+    for (i = 0; i < buf_size >> 1; i++) {
+        int xlow, xhigh, ihigh, ilow;
+        filter_samples(c, &samples[2*i], &xlow, &xhigh);
+        ihigh = encode_high(&c->band[1], xhigh);
+        ilow  = encode_low(&c->band[0], xlow);
+        update_high_predictor(&c->band[1], c->band[1].scale_factor *
+                              high_inv_quant[ihigh] >> 10, ihigh);
+        update_low_predictor(&c->band[0], ilow >> 2);
+        *dst++ = ihigh << 6 | ilow;
+    }
+    return i;
+}
+
+AVCodec adpcm_g722_encoder = {
+    .name           = "g722",
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = CODEC_ID_ADPCM_G722,
+    .priv_data_size = sizeof(G722Context),
+    .init           = g722_init,
+    .encode         = g722_encode_frame,
+    .long_name      = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
+    .sample_fmts    = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
+};
+#endif
 

-- 
Libav/FFmpeg packaging



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