atrac3plus: add support for GHA phase inversion.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/atrac3plus.c

@@ -1724,11 +1724,7 @@ static int decode_tones_info(GetBitContext *gb, Atrac3pChanUnitCtx *ctx,
     if (num_channels == 2) {
         get_subband_flags(gb, ctx->waves_info->tone_sharing, ctx->waves_info->num_tone_bands);
         get_subband_flags(gb, ctx->waves_info->tone_master,  ctx->waves_info->num_tone_bands);
-        if (get_subband_flags(gb, ctx->waves_info->phase_shift,
-                              ctx->waves_info->num_tone_bands)) {
-            avpriv_report_missing_feature(avctx, "GHA Phase shifting");
-            return AVERROR_PATCHWELCOME;
-        }
+        get_subband_flags(gb, ctx->waves_info->phase_shift, ctx->waves_info->num_tone_bands);
     }
 
     ctx->waves_info->tones_index = 0;

libavcodec/atrac3plusdsp.c

@@ -116,6 +116,7 @@ av_cold void ff_atrac3p_init_wave_synth(void)
  *  @param[in]    synth_param   ptr to common synthesis parameters
  *  @param[in]    waves_info    parameters for each sine wave
  *  @param[in]    envelope      envelope data for all waves in a group
+ *  @param[in]    fdsp          ptr to floating-point DSP context
  *  @param[in]    phase_shift   flag indicates 180° phase shift
  *  @param[in]    reg_offset    region offset for trimming envelope data
  *  @param[out]   out           receives sythesized data
@@ -123,6 +124,7 @@ av_cold void ff_atrac3p_init_wave_synth(void)
 static void waves_synth(Atrac3pWaveSynthParams *synth_param,
                         Atrac3pWavesData *waves_info,
                         Atrac3pWaveEnvelope *envelope,
+                        AVFloatDSPContext *fdsp,
                         int phase_shift, int reg_offset, float *out)
 {
     int i, wn, inc, pos;
@@ -146,6 +148,10 @@ static void waves_synth(Atrac3pWaveSynthParams *synth_param,
         }
     }
 
+    /* 180° phase shift if requested */
+    if (phase_shift)
+        fdsp->vector_fmul_scalar(out, out, -1.0f, 128);
+
     /* fade in with steep Hann window if requested */
     if (envelope->has_start_point) {
         pos = (envelope->start_pos << 2) - reg_offset;
@@ -216,11 +222,11 @@ void ff_atrac3p_generate_tones(Atrac3pChanUnitCtx *ch_unit, AVFloatDSPContext *f
     /* synthesize waves for both overlapping regions */
     if (tones_now->num_wavs && reg1_env_nonzero)
         waves_synth(ch_unit->waves_info_prev, tones_now, &tones_now->curr_env,
-                    ch_unit->waves_info_prev->phase_shift[sb] & ch_num,
+                    fdsp, ch_unit->waves_info_prev->phase_shift[sb] & ch_num,
                     128, wavreg1);
 
     if (tones_next->num_wavs && reg2_env_nonzero)
-        waves_synth(ch_unit->waves_info, tones_next, &tones_next->curr_env,
+        waves_synth(ch_unit->waves_info, tones_next, &tones_next->curr_env, fdsp,
                     ch_unit->waves_info->phase_shift[sb] & ch_num, 0, wavreg2);
 
     /* Hann windowing for non-faded wave signals */