Index: DOCS/man/en/mplayer.1
===================================================================
--- DOCS/man/en/mplayer.1	(revision 25343)
+++ DOCS/man/en/mplayer.1	(working copy)
@@ -4696,6 +4696,37 @@
 .PD 1
 .
 .TP
+.B lavcac3enc[=tospdif[:bitrate[:minchn]]]
+Encode multi-channel audio to AC-3 at runtime using libavcodec.
+Supports 16-bit native-endian input format, maximum 6 channels.
+The output is big-endian when outputting a raw AC-3 stream,
+native-endian when outputting to S/PDIF.
+The output sample rate of this filter is same with the input sample rate.
+When input sample rate is 48kHz, 44.1kHz, or 32kHz, this filter directly use it.
+Otherwise a resampler filter is auto-inserted before this filter to make
+the input and output sample rate be 48kHz.
+You need to specify '\-channels N' to make the decoder decode audio into
+N-channel, then the filter can encode the N-channel input to AC-3.
+.br
+.PD 0
+.RSs
+.IPs <tospdif>
+Output raw AC-3 stream if zero or not set,
+output to S/PDIF for passthrough when <tospdif> is set non-zero.
+.IPs <bitrate>
+The bitrate to encode the AC-3 stream.
+Set it to either 384 or 384000 to get 384kbits.
+Valid values: 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256,
+              320, 384, 448, 512, 576, 640
+Default bitrate is based on the input channel number:
+1ch: 96,  2ch: 192,  3ch: 224,  4ch: 384,  5ch: 448,  6ch: 448
+.IPs <minchn>
+If the input channel number is less than <minchn>, the filter will
+detach itself (default: 5).
+.RE
+.PD 1
+.
+.TP
 .B sweep[=speed]
 Produces a sine sweep.
 .PD 0
Index: libaf/af_lavcac3enc.c
===================================================================
--- libaf/af_lavcac3enc.c	(revision 0)
+++ libaf/af_lavcac3enc.c	(revision 0)
@@ -0,0 +1,301 @@
+/*
+ * audio filter for runtime AC-3 encoding with libavcodec.
+ *
+ * Copyright (C) 2007 Ulion <ulion A gmail P com>
+ *
+ * This file is part of MPlayer.
+ *
+ * MPlayer is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * MPlayer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MPlayer; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "config.h"
+#include "af.h"
+#include "help_mp.h"
+#include "reorder_ch.h"
+
+#include "avcodec.h"
+#include "ac3.h"
+
+// Data for specific instances of this filter
+typedef struct af_ac3enc_s {
+    struct AVCodec        *lavc_acodec;
+    struct AVCodecContext *lavc_actx;
+    int add_iec61937_header;
+    int bit_rate;
+    char *pending_data;
+    int pending_len;
+    int expect_len;
+    int min_channel_num;
+} af_ac3enc_t;
+
+extern int  avcodec_inited;
+
+// Initialization and runtime control
+static int control(struct af_instance_s *af, int cmd, void *arg)
+{
+    af_ac3enc_t *s  = (af_ac3enc_t *)af->setup;
+    af_data_t *data = (af_data_t *)arg;
+    int i, bit_rate, test_output_res;
+    static const int default_bit_rate[AC3_MAX_CHANNELS+1] = \
+        {0, 96000, 192000, 256000, 384000, 448000, 448000};
+
+    switch (cmd){
+    case AF_CONTROL_REINIT:
+        if (data->format == AF_FORMAT_AC3 || data->nch < s->min_channel_num)
+            return AF_DETACH;
+
+        s->pending_len = 0;
+        s->expect_len = AC3_FRAME_SIZE * data->nch * data->bps;
+        if (s->add_iec61937_header)
+            af->mul = (double)AC3_FRAME_SIZE * 2 * 2 / s->expect_len;
+        else
+            af->mul = (double)AC3_MAX_CODED_FRAME_SIZE / s->expect_len;
+
+        af_msg(AF_MSG_DEBUG0, "af_lavcac3enc reinit: %d, %d, %f, %d.\n",
+               data->nch, data->rate, af->mul, s->expect_len);
+
+        af->data->format = AF_FORMAT_S16_NE;
+        if (data->rate == 48000 || data->rate == 44100 || data->rate == 32000)
+            af->data->rate = data->rate;
+        else
+            af->data->rate = 48000;
+        if (data->nch > AC3_MAX_CHANNELS)
+            af->data->nch = AC3_MAX_CHANNELS;
+        else
+            af->data->nch = data->nch;
+        af->data->bps = 2;
+        test_output_res = af_test_output(af, data);
+
+        bit_rate = s->bit_rate ? s->bit_rate : default_bit_rate[af->data->nch];
+
+        if (s->lavc_actx->channels != af->data->nch ||
+                s->lavc_actx->sample_rate != af->data->rate ||
+                s->lavc_actx->bit_rate != bit_rate) {
+
+            if (s->lavc_actx->codec)
+                avcodec_close(s->lavc_actx);
+
+            // Put sample parameters
+            s->lavc_actx->channels = af->data->nch;
+            s->lavc_actx->sample_rate = af->data->rate;
+            s->lavc_actx->bit_rate = bit_rate;
+
+            if(avcodec_open(s->lavc_actx, s->lavc_acodec) < 0) {
+                af_msg(AF_MSG_ERROR, MSGTR_CouldntOpenCodec, "ac3", bit_rate);
+                return AF_ERROR;
+            }
+        }
+        af->data->format = AF_FORMAT_AC3;
+        af->data->nch = 2;
+        return test_output_res;
+    case AF_CONTROL_COMMAND_LINE:
+        af_msg(AF_MSG_DEBUG0, "af_lavcac3enc cmdline: %s.\n", (char*)arg);
+        s->bit_rate = 0;
+        s->min_channel_num = 0;
+        s->add_iec61937_header = 0;
+        sscanf((char*)arg,"%d:%d:%d", &s->add_iec61937_header, &s->bit_rate,
+               &s->min_channel_num);
+        if (s->bit_rate < 1000)
+            s->bit_rate *= 1000;
+        if (s->bit_rate) {
+            for (i = 0; i < 19; ++i)
+                if (ff_ac3_bitrate_tab[i] * 1000 == s->bit_rate)
+                    break;
+            if (i >= 19) {
+                af_msg(AF_MSG_WARN, "af_lavcac3enc unable set unsupported "
+                       "bitrate %d, use default bitrate (check manpage to see "
+                       "supported bitrates).\n", s->bit_rate);
+                s->bit_rate = 0;
+            }
+        }
+        if (s->min_channel_num == 0)
+            s->min_channel_num = 5;
+        af_msg(AF_MSG_VERBOSE, "af_lavcac3enc config spdif:%d, bitrate:%d, "
+               "minchnum:%d.\n", s->add_iec61937_header, s->bit_rate,
+               s->min_channel_num);
+        return AF_OK;
+    }
+    return AF_UNKNOWN;
+}
+
+// Deallocate memory
+static void uninit(struct af_instance_s* af)
+{
+    if (af->data)
+        free(af->data->audio);
+    free(af->data);
+    if (af->setup) {
+        af_ac3enc_t *s = af->setup;
+        af->setup = NULL;
+        if(s->lavc_actx) {
+            if (s->lavc_actx->codec)
+                avcodec_close(s->lavc_actx);
+            free(s->lavc_actx);
+        }
+        free(s->pending_data);
+        free(s);
+    }
+}
+
+// Filter data through filter
+static af_data_t* play(struct af_instance_s* af, af_data_t* data)
+{
+    af_ac3enc_t *s = af->setup;
+    af_data_t *c = data;    // Current working data
+    af_data_t *l;
+    int len, left, outsize = 0, destsize;
+    char *buf, *src, *dest;
+
+    if (AF_OK != RESIZE_LOCAL_BUFFER(af,data))
+        return NULL;
+
+    l = af->data;           // Local data
+    buf = (char *)l->audio;
+    src = (char *)c->audio;
+    left = c->len;
+
+
+    while (left > 0) {
+        if (left + s->pending_len < s->expect_len) {
+            memcpy(s->pending_data + s->pending_len, src, left);
+            src += left;
+            s->pending_len += left;
+            left = 0;
+            break;
+        }
+
+        dest = s->add_iec61937_header ? buf + 8 : buf;
+        destsize = (char *)l->audio + l->len - buf;
+
+        if (s->pending_len) {
+            int needs = s->expect_len - s->pending_len;
+            if (needs > 0) {
+                memcpy(s->pending_data + s->pending_len, src, needs);
+                src += needs;
+                left -= needs;
+            }
+
+            if (c->nch >= 5)
+                reorder_channel_nch(s->pending_data,
+                                    AF_CHANNEL_LAYOUT_MPLAYER_DEFAULT,
+                                    AF_CHANNEL_LAYOUT_LAVC_AC3_DEFAULT,
+                                    c->nch,
+                                    s->expect_len / 2, 2);
+
+            len = avcodec_encode_audio(s->lavc_actx, dest, destsize,
+                                       (void *)s->pending_data);
+            s->pending_len = 0;
+        }
+        else {
+            if (c->nch >= 5)
+                reorder_channel_nch(src,
+                                    AF_CHANNEL_LAYOUT_MPLAYER_DEFAULT,
+                                    AF_CHANNEL_LAYOUT_LAVC_AC3_DEFAULT,
+                                    c->nch,
+                                    s->expect_len / 2, 2);
+            len = avcodec_encode_audio(s->lavc_actx,dest,destsize,(void *)src);
+            src += s->expect_len;
+            left -= s->expect_len;
+        }
+        af_msg(AF_MSG_DEBUG0, "avcodec_encode_audio got %d, pending %d.\n",
+               len, s->pending_len);
+
+        if (s->add_iec61937_header) {
+            int16_t *out = (int16_t *)buf;
+            int bsmod = dest[5] & 0x7;
+
+#ifndef WORDS_BIGENDIAN
+            int i;
+            char tmp;
+            for (i = 0; i < len; i += 2) {
+                tmp = dest[i];
+                dest[i] = dest[i+1];
+                dest[i+1] = tmp;
+            }
+            if (len & 1) {
+                dest[len] = dest[len-1];
+                dest[len-1] = 0;
+                len++;
+            }
+#endif
+            out[0] = 0xF872;   // iec 61937 syncword 1
+            out[1] = 0x4E1F;   // iec 61937 syncword 2
+            out[2] = 0x0001;   // data-type ac3
+            out[2] |= bsmod << 8; // bsmod
+            out[3] = len << 3; // number of bits in payload
+
+            memset(buf + 8 + len, 0, AC3_FRAME_SIZE * 2 * 2 - 8 - len);
+            len = AC3_FRAME_SIZE * 2 * 2;
+        }
+
+        outsize += len;
+        buf += len;
+    }
+    c->audio = l->audio;
+    c->nch   = 2;
+    c->bps   = 2;
+    c->len   = outsize;
+    af_msg(AF_MSG_DEBUG0, "play return size %d, pending %d\n",
+           outsize, s->pending_len);
+    return c;
+}
+
+static int af_open(af_instance_t* af){
+
+    af_ac3enc_t *s = calloc(1,sizeof(af_ac3enc_t));
+    int pending_space = 2 * AC3_MAX_CHANNELS * AC3_FRAME_SIZE;
+    s->pending_data = calloc(pending_space, sizeof(char));
+
+    af->control=control;
+    af->uninit=uninit;
+    af->play=play;
+    af->mul=1;
+    af->data=calloc(1,sizeof(af_data_t));
+    af->setup=s;
+
+    if (!avcodec_inited){
+        avcodec_init();
+        avcodec_register_all();
+        avcodec_inited=1;
+    }
+
+    s->lavc_acodec = avcodec_find_encoder_by_name("ac3");
+    if (!s->lavc_acodec) {
+        af_msg(AF_MSG_ERROR, MSGTR_LavcAudioCodecNotFound, "ac3");
+        return AF_ERROR;
+    }
+
+    s->lavc_actx = avcodec_alloc_context();
+    if (!s->lavc_actx) {
+        af_msg(AF_MSG_ERROR, MSGTR_CouldntAllocateLavcContext);
+        return AF_ERROR;
+    }
+
+    return AF_OK;
+}
+
+af_info_t af_info_lavcac3enc = {
+    "runtime encode to ac3 using libavcodec",
+    "lavcac3enc",
+    "Ulion",
+    "",
+    AF_FLAGS_REENTRANT,
+    af_open
+};
Index: libaf/Makefile
===================================================================
--- libaf/Makefile	(revision 25343)
+++ libaf/Makefile	(working copy)
@@ -32,5 +32,6 @@
 
 SRCS_COMMON-$(HAVE_SYS_MMAN_H)      += af_export.c
 SRCS_COMMON-$(LIBAVCODEC)           += af_lavcresample.c
+SRCS_COMMON-$(LIBAVCODEC_A)         += af_lavcac3enc.c
 
 include ../mpcommon.mak
Index: libaf/af.c
===================================================================
--- libaf/af.c	(revision 25342)
+++ libaf/af.c	(working copy)
@@ -24,6 +24,7 @@
 extern af_info_t af_info_export;
 extern af_info_t af_info_volnorm;
 extern af_info_t af_info_extrastereo;
+extern af_info_t af_info_lavcac3enc;
 extern af_info_t af_info_lavcresample;
 extern af_info_t af_info_sweep;
 extern af_info_t af_info_hrtf;
@@ -51,6 +52,9 @@
 #endif
    &af_info_volnorm,
    &af_info_extrastereo,
+#ifdef USE_LIBAVCODEC_A
+   &af_info_lavcac3enc,
+#endif
 #ifdef USE_LIBAVCODEC
    &af_info_lavcresample,
 #endif