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fix resamplers.

PATCH In review James Courtier-Dutton 1 participant 3 messages Jul 21, 2004

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James Courtier-Dutton

author
#0 lore raw

PATCH 1/1 fix resamplers.

The current pcm_rate.c tends to insert zero samples in the stream.

E.g. Downsampling from 48000 -> 16000
Starts with a block of 2048, and has to create 682 samples.
The current code sometimes only produces 681 samples, leaving the last one zero.

The attached patch fixes this problem.

James

? alsa-lib/ltconfig
? alsa-lib/src/pcm/pcm_rate.c.org
Index: alsa-lib/src/pcm/pcm_rate.c
===================================================================
RCS file: /cvsroot/alsa/alsa-lib/src/pcm/pcm_rate.c,v retrieving revision 1.84

src/pcm/pcm_rate.c +15 -15
diff -u -r1.84 pcm_rate.c
@@ -585,47 +585,47 @@
 		do {
 			snd_pcm_uframes_t cframes;
 			
-			cframes = snd_pcm_rate_client_frames(pcm, slave->period_size - 1);
-			if (cframes == pcm->period_size - 1)
+			cframes = snd_pcm_rate_client_frames(pcm, slave->period_size);
+			if (cframes == pcm->period_size)
 				break;
-			if (cframes > pcm->period_size - 1) {
+			if (cframes > pcm->period_size) {
 				rate->pitch++;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size - 1) < pcm->period_size - 1) {
-					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
+				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size) < pcm->period_size) {
+					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size, pcm->period_size);
 					return -EIO;
 				}
 			} else {
 				rate->pitch--;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size - 1) > pcm->period_size - 1) {
+				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size) > pcm->period_size) {
 					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
 					return -EIO;
 				}
 			}
 		} while (1);
-		assert((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size - 1) == pcm->period_size - 1);
+		assert((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size) == pcm->period_size);
 	} else {
 		rate->pitch = (((u_int64_t)pcm->period_size * LINEAR_DIV) + slave->period_size - 1) / slave->period_size;
 		do {
 			snd_pcm_uframes_t cframes;
 			
-			cframes = snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1);
-			if (cframes == slave->period_size - 1)
+			cframes = snd_pcm_rate_slave_frames(pcm, pcm->period_size);
+			if (cframes == slave->period_size)
 				break;
-			if (cframes > slave->period_size - 1) {
+			if (cframes > slave->period_size) {
 				rate->pitch++;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1) < slave->period_size - 1) {
-					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
+				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size) < slave->period_size) {
+					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size, pcm->period_size);
 					return -EIO;
 				}
 			} else {
 				rate->pitch--;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1) > slave->period_size - 1) {
-					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
+				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size) > slave->period_size) {
+					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size, pcm->period_size);
 					return -EIO;
 				}
 			}
 		} while (1);
-		assert((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1) == slave->period_size - 1);
+		assert((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size) == slave->period_size);
 	}
 	recalc(pcm, &sparams->avail_min);
 	rate->orig_avail_min = sparams->avail_min;
author
#1 lore raw
Quoted 11 lines · James Courtier-Dutton

The current pcm_rate.c tends to insert zero samples in the stream.

E.g. Downsampling from 48000 -> 16000
Starts with a block of 2048, and has to create 682 samples.
The current code sometimes only produces 681 samples, leaving the last one zero.

The attached patch fixes this problem.

James

I have done more testing, and it does not quite fix everything.

James

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author
#2 lore raw
Quoted 10 lines · James Courtier-Dutton
Quoted 8 lines · James Courtier-Dutton

The current pcm_rate.c tends to insert zero samples in the stream.

E.g. Downsampling from 48000 -> 16000
Starts with a block of 2048, and has to create 682 samples.
The current code sometimes only produces 681 samples, leaving the last one zero.

The attached patch fixes this problem.

Quoted 10 lines
Quoted 3 lines

James

I have done more testing, and it does not quite fix everything.

James

This PATCH against alsa-lib cvs seems to work well for me now. Can some people please try it and tell me what they think ?

Thanks
James

RCS file: /cvsroot/alsa/alsa-lib/src/pcm/pcm_rate.c,v retrieving revision 1.84

src/pcm/pcm_rate.c +22 -22
diff -u -r1.84 pcm_rate.c
@@ -254,9 +254,9 @@
 		return 0;
 	/* Round toward zero */
 	if (pcm->stream == SND_PCM_STREAM_PLAYBACK)
-		return muldiv_down(frames, LINEAR_DIV, rate->pitch);
+		return muldiv_near(frames, LINEAR_DIV, rate->pitch);
 	else
-		return muldiv_down(frames, rate->pitch, LINEAR_DIV);
+		return muldiv_near(frames, rate->pitch, LINEAR_DIV);
 }
 
 static snd_pcm_sframes_t snd_pcm_rate_slave_frames(snd_pcm_t *pcm, snd_pcm_sframes_t frames)

@@ -264,9 +264,9 @@
 	snd_pcm_rate_t *rate = pcm->private_data;
 	/* Round toward zero */
 	if (pcm->stream == SND_PCM_STREAM_PLAYBACK)
-		return muldiv_down(frames, rate->pitch, LINEAR_DIV);
+		return muldiv_near(frames, rate->pitch, LINEAR_DIV);
 	else
-		return muldiv_down(frames, LINEAR_DIV, rate->pitch);
+		return muldiv_near(frames, LINEAR_DIV, rate->pitch);
 }
 
 static int snd_pcm_rate_hw_refine_cprepare(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params)

@@ -581,51 +581,51 @@
 	params->boundary = boundary1;
 	sparams->boundary = boundary2;
 	if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
-		rate->pitch = (((u_int64_t)slave->period_size * LINEAR_DIV) + pcm->period_size - 1) / pcm->period_size;
+		rate->pitch = (((u_int64_t)slave->period_size * LINEAR_DIV) + pcm->period_size ) / pcm->period_size;
 		do {
 			snd_pcm_uframes_t cframes;
 			
-			cframes = snd_pcm_rate_client_frames(pcm, slave->period_size - 1);
-			if (cframes == pcm->period_size - 1)
+			cframes = snd_pcm_rate_client_frames(pcm, slave->period_size );
+			if (cframes == pcm->period_size )
 				break;
-			if (cframes > pcm->period_size - 1) {
+			if (cframes > pcm->period_size ) {
 				rate->pitch++;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size - 1) < pcm->period_size - 1) {
-					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
+				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size) < pcm->period_size - 1) {
+					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size, pcm->period_size);
 					return -EIO;
 				}
 			} else {
 				rate->pitch--;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size - 1) > pcm->period_size - 1) {
-					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
+				if ((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size) > pcm->period_size) {
+					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size, pcm->period_size);
 					return -EIO;
 				}
 			}
 		} while (1);
-		assert((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size - 1) == pcm->period_size - 1);
+		assert((snd_pcm_uframes_t)snd_pcm_rate_client_frames(pcm, slave->period_size ) == pcm->period_size );
 	} else {
-		rate->pitch = (((u_int64_t)pcm->period_size * LINEAR_DIV) + slave->period_size - 1) / slave->period_size;
+		rate->pitch = (((u_int64_t)pcm->period_size * LINEAR_DIV) + slave->period_size ) / slave->period_size;
 		do {
 			snd_pcm_uframes_t cframes;
 			
-			cframes = snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1);
-			if (cframes == slave->period_size - 1)
+			cframes = snd_pcm_rate_slave_frames(pcm, pcm->period_size );
+			if (cframes == slave->period_size )
 				break;
-			if (cframes > slave->period_size - 1) {
+			if (cframes > slave->period_size ) {
 				rate->pitch++;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1) < slave->period_size - 1) {
-					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
+				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size ) < slave->period_size ) {
+					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size, pcm->period_size);
 					return -EIO;
 				}
 			} else {
 				rate->pitch--;
-				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1) > slave->period_size - 1) {
-					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size - 1, pcm->period_size - 1);
+				if ((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size) > slave->period_size ) {
+					SNDERR("Unable to satisfy pitch condition (%i/%i - %li/%li)\n", slave->rate, pcm->rate, slave->period_size , pcm->period_size );
 					return -EIO;
 				}
 			}
 		} while (1);
-		assert((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size - 1) == slave->period_size - 1);
+		assert((snd_pcm_uframes_t)snd_pcm_rate_slave_frames(pcm, pcm->period_size ) == slave->period_size );
 	}
 	recalc(pcm, &sparams->avail_min);
 	rate->orig_avail_min = sparams->avail_min;