Change decode_audio() interface

Rewrite decode_audio to better deal with filters that handle input in
large blocks. It now always places output in sh_audio->a_out_buffer
(which was always given as a parameter before) and reallocates the
buffer if needed. After the changes filters can return arbitrarily
large blocks of data without some of it being lost. The new version
also allows simplifying some code.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@24920 b3059339-0415-0410-9bf9-f77b7e298cf2

6 files changed, 115 insertions, 133 deletions

diff --git a/libaf/af.c b/libaf/af.c
index 5eda4ff5b1..b86bfe3d14 100644
--- a/libaf/af.c
+++ b/libaf/af.c
@@ -526,19 +526,9 @@ int af_lencalc(double mul, af_data_t* d)
   return d->len * mul + t + 1;
 }
 
-/* Calculate how long the input IN to the filters should be to produce
-   a certain output length OUT but with the following three constraints:
-   1. IN <= max_insize, where max_insize is the maximum possible input
-      block length
-   2. OUT <= max_outsize, where max_outsize is the maximum possible
-      output block length
-   3. If possible OUT >= len. 
-   Return -1 in case of error */ 
-int af_calc_insize_constrained(af_stream_t* s, int len,
-			       int max_outsize,int max_insize)
+// Calculate average ratio of filter output size to input size
+double af_calc_filter_multiplier(af_stream_t* s)
 {
-  int t   = s->input.bps*s->input.nch;
-  int in  = 0;
   af_instance_t* af=s->first; 
   double mul = 1;
   // Iterate through all filters and calculate total multiplication factor
@@ -547,14 +537,7 @@ int af_calc_insize_constrained(af_stream_t* s, int len,
       af=af->next;
   }while(af);
 
-  if (len > max_outsize)
-      len = max_outsize;
-
-  in = len / t / mul * t;
-
-  if(in>max_insize) in=t*(max_insize/t);
-
-  return in;
+  return mul;
 }
 
 /* Calculate the total delay [ms] caused by the filters */
diff --git a/libaf/af.h b/libaf/af.h
index 428f53ff6e..4c983cb6e4 100644
--- a/libaf/af.h
+++ b/libaf/af.h
@@ -189,22 +189,10 @@ af_data_t* af_play(af_stream_t* s, af_data_t* data);
 af_instance_t *af_control_any_rev (af_stream_t* s, int cmd, void* arg);
 
 /**
- * \brief calculate required input length for desired output size
- * \param len desired minimum output length
- * \param max_outsize maximum output length
- * \param max_insize maximum input length
- * \return input length or -1 on error
- *
-   Calculate how long the input IN to the filters should be to produce
-   a certain output length OUT but with the following three constraints:
-   1. IN <= max_insize, where max_insize is the maximum possible input
-      block length
-   2. OUT <= max_outsize, where max_outsize is the maximum possible
-      output block length
-   3. If possible OUT >= len. 
- */ 
-int af_calc_insize_constrained(af_stream_t* s, int len,
-			       int max_outsize,int max_insize);
+ * \brief calculate average ratio of filter output lenth to input length
+ * \return the ratio
+ */
+double af_calc_filter_multiplier(af_stream_t* s);
 
 /**
  * \brief Calculate the total delay caused by the filters
diff --git a/libmpcodecs/dec_audio.c b/libmpcodecs/dec_audio.c
index 5445eeac22..ee6295d2ca 100644
--- a/libmpcodecs/dec_audio.c
+++ b/libmpcodecs/dec_audio.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <assert.h>
 
 #include "config.h"
 #include "mp_msg.h"
@@ -380,86 +381,113 @@ int init_audio_filters(sh_audio_t *sh_audio, int in_samplerate,
     return 1;
 }
 
-int decode_audio(sh_audio_t *sh_audio, unsigned char *buf, int minlen,
-		 int maxlen)
+static int filter_n_bytes(sh_audio_t *sh, int len)
 {
-    int declen;
-    af_data_t afd;		// filter input
-    af_data_t *pafd;		// filter output
-    ad_functions_t *mpadec = sh_audio->ad_driver;
-
-    if (!sh_audio->inited || !sh_audio->afilter)
-	abort();
-
-    declen = af_calc_insize_constrained(sh_audio->afilter, minlen, maxlen,
-					sh_audio->a_buffer_size -
-					sh_audio->audio_out_minsize);
-
-    mp_msg(MSGT_DECAUDIO, MSGL_DBG2,
-	   "\ndecaudio: minlen=%d maxlen=%d declen=%d (max=%d)\n", minlen,
-	   maxlen, declen, sh_audio->a_buffer_size);
-
-    if (declen <= 0)
-	return -1;		// error!
-
-    while (declen > sh_audio->a_buffer_len) {
-	int len = declen - sh_audio->a_buffer_len;
-	int maxlen = sh_audio->a_buffer_size - sh_audio->a_buffer_len;
-
-	mp_msg(MSGT_DECAUDIO, MSGL_DBG2,
-	       "decaudio: decoding %d bytes, max: %d (%d)\n", len, maxlen,
-	       sh_audio->audio_out_minsize);
-
-	// When a decoder sets audio_out_minsize that should guarantee it can
-	// write up to audio_out_minsize bytes at a time until total >= minlen
-	// without checking maxlen. Thus maxlen must be at least minlen +
-	// audio_out_minsize. Check that to guard against buffer overflows.
-	if (maxlen < len + sh_audio->audio_out_minsize)
+    assert(len-1 + sh->audio_out_minsize <= sh->a_buffer_size);
+
+    int error = 0;
+
+    // Decode more bytes if needed
+    while (sh->a_buffer_len < len) {
+	unsigned char *buf = sh->a_buffer + sh->a_buffer_len;
+	int minlen = len - sh->a_buffer_len;
+	int maxlen = sh->a_buffer_size - sh->a_buffer_len;
+	int ret = sh->ad_driver->decode_audio(sh, buf, minlen, maxlen);
+	if (ret <= 0) {
+	    error = -1;
+	    len = sh->a_buffer_len;
 	    break;
+	}
+	sh->a_buffer_len += ret;
+    }
 
-	len = mpadec->decode_audio(sh_audio,
-				   sh_audio->a_buffer + sh_audio->a_buffer_len,
-				   len, maxlen);
-	if (len <= 0)
-	    break;		// EOF?
-	sh_audio->a_buffer_len += len;
+    // Filter
+    af_data_t filter_input = {
+	.audio = sh->a_buffer,
+	.len = len,
+	.rate = sh->samplerate,
+	.nch = sh->channels,
+	.format = sh->sample_format
+    };
+    af_fix_parameters(&filter_input);
+    af_data_t *filter_output = af_play(sh->afilter, &filter_input);
+    if (!filter_output)
+	return -1;
+    if (sh->a_out_buffer_size < sh->a_out_buffer_len + filter_output->len) {
+	int newlen = sh->a_out_buffer_len + filter_output->len;
+	mp_msg(MSGT_DECAUDIO, MSGL_V, "Increasing filtered audio buffer size "
+	       "from %d to %d\n", sh->a_out_buffer_size, newlen);
+	sh->a_out_buffer = realloc(sh->a_out_buffer, newlen);
+	sh->a_out_buffer_size = newlen;
     }
-    if (declen > sh_audio->a_buffer_len)
-	declen = sh_audio->a_buffer_len;   // still no enough data (EOF) :(
-
-    // run the filters:
-    afd.audio = sh_audio->a_buffer;
-    afd.len = declen;
-    afd.rate = sh_audio->samplerate;
-    afd.nch = sh_audio->channels;
-    afd.format = sh_audio->sample_format;
-    af_fix_parameters(&afd);
-    pafd = af_play(sh_audio->afilter, &afd);
-
-    if (!pafd)
-	return -1;   // error
-
-    mp_msg(MSGT_DECAUDIO, MSGL_DBG2, "decaudio: declen=%d out=%d (max %d)\n",
-	   declen, pafd->len, maxlen);
-
-    // copy filter==>out:
-    if (maxlen < pafd->len) {
-	af_stream_t *afs = sh_audio->afilter;
-	maxlen -= maxlen % (afs->output.nch * afs->output.bps);
-	mp_msg(MSGT_DECAUDIO, MSGL_WARN,
-	     "%i bytes of audio data lost due to buffer overflow, len = %i\n",
-	       pafd->len - maxlen, pafd->len);
-    } else
-	maxlen = pafd->len;
-    memmove(buf, pafd->audio, maxlen);
+    memcpy(sh->a_out_buffer + sh->a_out_buffer_len, filter_output->audio,
+	   filter_output->len);
+    sh->a_out_buffer_len += filter_output->len;
 
     // remove processed data from decoder buffer:
-    sh_audio->a_buffer_len -= declen;
-    if (sh_audio->a_buffer_len > 0)
-	memmove(sh_audio->a_buffer, sh_audio->a_buffer + declen,
-		sh_audio->a_buffer_len);
+    sh->a_buffer_len -= len;
+    memmove(sh->a_buffer, sh->a_buffer + len, sh->a_buffer_len);
 
-    return maxlen;
+    return error;
+}
+
+/* Try to get at least minlen decoded+filtered bytes in sh_audio->a_out_buffer
+ * (total length including possible existing data).
+ * Return 0 on success, -1 on error/EOF (not distinguished).
+ * In the former case sh_audio->a_out_buffer_len is always >= minlen
+ * on return. In case of EOF/error it might or might not be.
+ * Can reallocate sh_audio->a_out_buffer if needed to fit all filter output. */
+int decode_audio(sh_audio_t *sh_audio, int minlen)
+{
+    if (!sh_audio->inited || !sh_audio->afilter)
+	abort();
+
+    // Decoded audio must be cut at boundaries of this many bytes
+    int unitsize = sh_audio->channels * sh_audio->samplesize;
+
+    /* Filter output size will be about filter_multiplier times input size.
+     * If some filter buffers audio in big blocks this might only hold
+     * as average over time. */
+    double filter_multiplier = af_calc_filter_multiplier(sh_audio->afilter);
+
+    /* If the decoder set audio_out_minsize then it can do the equivalent of
+     * "while (output_len < target_len) output_len += audio_out_minsize;",
+     * so we must guarantee there is at least audio_out_minsize-1 bytes
+     * more space in the output buffer than the minimum length we try to
+     * decode. */
+    int max_decode_len = sh_audio->a_buffer_size - sh_audio->audio_out_minsize;
+    max_decode_len -= max_decode_len % unitsize;
+
+    while (sh_audio->a_out_buffer_len < minlen) {
+	int declen = (minlen - sh_audio->a_out_buffer_len) / filter_multiplier
+	    + (unitsize << 5); // some extra for possible filter buffering
+	if (declen > max_decode_len) {  // Do it in several steps
+	    if (filter_n_bytes(sh_audio, max_decode_len) < 0)
+		return -1;
+	    continue;
+	}
+	declen -= declen % unitsize;
+	if (filter_n_bytes(sh_audio, declen) < 0)
+	    return -1;
+	if (sh_audio->a_out_buffer_len >= minlen)
+	    return 0;
+	/* Some filter must be doing significant buffering if the estimated
+	 * input length didn't produce enough output from filters.
+	 * Feed the filters 2k bytes at a time until we have enough output.
+	 * Very small amounts could make filtering inefficient while large
+	 * amounts can make MPlayer demux the file unnecessarily far ahead
+	 * to get audio data and buffer video frames in memory while doing
+	 * so. However the performance impact of either is probably not too
+	 * significant as long as the value is not completely insane. */
+	declen = min(2000, max_decode_len);
+	declen -= declen % unitsize;
+	while (sh_audio->a_out_buffer_len < minlen) {
+	    if (filter_n_bytes(sh_audio, declen) < 0)
+		return -1;
+	}
+	return 0;
+    }
+    return 0;
 }
 
 void resync_audio_stream(sh_audio_t *sh_audio)
diff --git a/libmpcodecs/dec_audio.h b/libmpcodecs/dec_audio.h
index d372a65fc8..e5d71b8792 100644
--- a/libmpcodecs/dec_audio.h
+++ b/libmpcodecs/dec_audio.h
@@ -2,7 +2,7 @@
 // dec_audio.c:
 extern void afm_help(void);
 extern int init_best_audio_codec(sh_audio_t *sh_audio,char** audio_codec_list,char** audio_fm_list);
-extern int decode_audio(sh_audio_t *sh_audio,unsigned char *buf,int minlen,int maxlen);
+extern int decode_audio(sh_audio_t *sh_audio, int minlen);
 extern void resync_audio_stream(sh_audio_t *sh_audio);
 extern void skip_audio_frame(sh_audio_t *sh_audio);
 extern void uninit_audio(sh_audio_t *sh_audio);
diff --git a/mencoder.c b/mencoder.c
index 9ef7835c8f..219f3ff79c 100644
--- a/mencoder.c
+++ b/mencoder.c
@@ -337,14 +337,7 @@ static int dec_audio(sh_audio_t *sh_audio,unsigned char* buffer,int total){
     while(size<total && !at_eof){
 	int len=total-size;
 		if(len>MAX_OUTBURST) len=MAX_OUTBURST;
-		if(len>sh_audio->a_out_buffer_size) len=sh_audio->a_out_buffer_size;
-		if(len>sh_audio->a_out_buffer_len){
-		    int ret=decode_audio(sh_audio,
-			&sh_audio->a_out_buffer[sh_audio->a_out_buffer_len],
-    			len-sh_audio->a_out_buffer_len,
-			sh_audio->a_out_buffer_size-sh_audio->a_out_buffer_len);
-		    if(ret>0) sh_audio->a_out_buffer_len+=ret; else at_eof=1;
-		}
+		if (decode_audio(sh_audio, len) < 0) at_eof=1;
 		if(len>sh_audio->a_out_buffer_len) len=sh_audio->a_out_buffer_len;
 		fast_memcpy(buffer+size,sh_audio->a_out_buffer,len);
 		sh_audio->a_out_buffer_len-=len; size+=len;
diff --git a/mplayer.c b/mplayer.c
index 9b7c87ba64..205864a254 100644
--- a/mplayer.c
+++ b/mplayer.c
@@ -1779,22 +1779,12 @@ static int fill_audio_out_buffers(void)
 	// Fill buffer if needed:
 	current_module="decode_audio";
 	t = GetTimer();
-	while (sh_audio->a_out_buffer_len < playsize) {
-	    int buflen = sh_audio->a_out_buffer_len;
-	    int ret = decode_audio(sh_audio, &sh_audio->a_out_buffer[buflen],
-				   playsize - buflen, // min bytes
-				   sh_audio->a_out_buffer_size - buflen // max
-				   );
-	    if (ret <= 0) { // EOF?
-		if (mpctx->d_audio->eof) {
-		    audio_eof = 1;
-		    if (sh_audio->a_out_buffer_len == 0)
-			return 0;
-		}
-		break;
+	if (decode_audio(sh_audio, playsize) < 0) // EOF or error
+	    if (mpctx->d_audio->eof) {
+		audio_eof = 1;
+		if (sh_audio->a_out_buffer_len == 0)
+		    return 0;
 	    }
-	    sh_audio->a_out_buffer_len += ret;
-	}
 	t = GetTimer() - t;
 	tt = t*0.000001f; audio_time_usage+=tt;
 	if (playsize > sh_audio->a_out_buffer_len) {