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simplified bandwidth setting; modified ABR code

--- a/libfaac/frame.c

+++ b/libfaac/frame.c

@@ -156,73 +156,18 @@

     if (config->bitRate && !config->bandWidth)

     {

-		static struct {

-			int rate; // per channel at 44100 sampling frequency

-			int cutoff;

-		}	rates[] = {

-#ifdef DRM

-            /* DRM uses low bit-rates. We've chosen higher bandwidth values and

-               decrease the quantizer quality at the same time to preserve the

-               low bit-rate */

-            {4500,  1200},

-            {9180,  2500},

-            {11640, 3000},

-            {14500, 4000},

-            {17460, 5500},

-            {20960, 6250},

-            {40000, 12000},

-#else

-			{29500, 5000},

-			{37500, 7000},

-			{47000, 10000},

-			{64000, 16000},

-			{76000, 20000},

-			{128000, 20000},

-#endif

-			{0, 0}

-		};

-

-		int f0, f1;

-		int r0, r1;

-

-#ifdef DRM

-        double tmpbitRate = (double)config->bitRate;

-#else

-        double tmpbitRate = (double)config->bitRate * 44100 / hEncoder->sampleRate;

-#endif

-

-        config->quantqual = 100;

-

-		f0 = f1 = rates[0].cutoff;

-		r0 = r1 = rates[0].rate;

-		

-		for (i = 0; rates[i].rate; i++)

-		{

-			f0 = f1;

-			f1 = rates[i].cutoff;

-			r0 = r1;

-			r1 = rates[i].rate;

-			if (rates[i].rate >= tmpbitRate)

-				break;

-		}

-

-        if (tmpbitRate > r1)

-            tmpbitRate = r1;

-        if (tmpbitRate < r0)

-            tmpbitRate = r0;

-

-		if (f1 > f0)

-            config->bandWidth =

-                    pow((double)tmpbitRate / r1,

-                    log((double)f1 / f0) / log ((double)r1 / r0)) * (double)f1;

-		else

-			config->bandWidth = f1;

-

-#ifndef DRM

         config->bandWidth = (double)config->bitRate * hEncoder->sampleRate * bwfac / 60000.0;

-#endif

+        if (!config->quantqual)

+        {

+            config->quantqual = (double)config->bitRate * hEncoder->numChannels / 1280;

+            if (config->quantqual > 100)

+                config->quantqual = (config->quantqual - 100) * 3.0 + 100;

+        }

     }

+    if (!config->quantqual)

+        config->quantqual = DEFQUAL;

+

     hEncoder->config.bitRate = config->bitRate;

     if (!config->bandWidth)

@@ -312,7 +257,7 @@

     hEncoder->config.useTns = 0;

     hEncoder->config.bitRate = 0; /* default bitrate / channel */

     hEncoder->config.bandWidth = bwfac * hEncoder->sampleRate;

-    hEncoder->config.quantqual = DEFQUAL;

+    hEncoder->config.quantqual = 0;

     hEncoder->config.psymodellist = (psymodellist_t *)psymodellist;

     hEncoder->config.psymodelidx = 0;

     hEncoder->psymodel =

@@ -726,26 +671,27 @@

     /* Adjust quality to get correct average bitrate */

     if (hEncoder->config.bitRate)

-	{

-		double fix;

-		int desbits = numChannels * (hEncoder->config.bitRate * FRAME_LEN)

-				/ hEncoder->sampleRate;

-		int diff = (frameBytes * 8) - desbits;

+    {

+        int desbits = numChannels * (hEncoder->config.bitRate * FRAME_LEN)

+            / hEncoder->sampleRate;

+        double fix = (double)desbits / (double)(frameBytes * 8);

-		hEncoder->bitDiff += diff;

-		fix = (double)hEncoder->bitDiff / desbits;

-		fix *= 0.01;

-		fix = max(fix, -0.2);

-		fix = min(fix, 0.2);

+        if (fix < 0.9)

+            fix += 0.1;

+        else if (fix > 1.1)

+            fix -= 0.1;

+        else

+            fix = 1.0;

-		if (((diff > 0) && (fix > 0.0)) || ((diff < 0) && (fix < 0.0)))

-		{

-			hEncoder->aacquantCfg.quality *= (1.0 - fix);

-                        if (hEncoder->aacquantCfg.quality > maxqual)

-                            hEncoder->aacquantCfg.quality = maxqual;

-            if (hEncoder->aacquantCfg.quality < 50)

-                hEncoder->aacquantCfg.quality = 50;

-		}

+        fix = (fix - 1.0) * 0.5 + 1.0;

+        // printf("q: %.1f(f:%.4f)\n", hEncoder->aacquantCfg.quality, fix);

+

+        hEncoder->aacquantCfg.quality *= fix;

+

+        if (hEncoder->aacquantCfg.quality > maxqual)

+            hEncoder->aacquantCfg.quality = maxqual;

+        if (hEncoder->aacquantCfg.quality < 10)

+            hEncoder->aacquantCfg.quality = 10;

     }

 #endif

--- a/libfaac/frame.h

+++ b/libfaac/frame.h

@@ -105,11 +105,8 @@

     /* quantizer specific config */

     AACQuantCfg aacquantCfg;

-	/* FFT Tables */

-	FFT_Tables	fft_tables;

-

-    /* output bits difference in average bitrate mode */

-    int bitDiff;

+    /* FFT Tables */

+    FFT_Tables	fft_tables;

 } faacEncStruct;

 #pragma pack(pop)