@@ -29,6 +29,7 @@ version <next>:

 - iLBC encoding/decoding via libilbc

 - Microsoft Screen 1 decoder

 - join audio filter

+- audio channel mapping filter

 version 0.8:

@@ -232,6 +232,39 @@ front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'

 side_right.wav

 @end example

+@section channelmap

+Remap input channels to new locations.

+

+This filter accepts the following named parameters:

+@table @option

+@item channel_layout

+Channel layout of the output stream.

+

+@item map

+Map channels from input to output. The argument is a comma-separated list of

+mappings, each in the @code{@var{in_channel}-@var{out_channel}} or

+@var{in_channel} form. @var{in_channel} can be either the name of the input

+channel (e.g. FL for front left) or its index in the input channel layout.

+@var{out_channel} is the name of the output channel or its index in the output

+channel layout. If @var{out_channel} is not given then it is implicitly an

+index, starting with zero and increasing by one for each mapping.

+@end table

+

+If no mapping is present, the filter will implicitly map input channels to

+output channels preserving index.

+

+For example, assuming a 5.1+downmix input MOV file

+@example

+avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav

+@end example

+will create an output WAV file tagged as stereo from the downmix channels of

+the input.

+

+To fix a 5.1 WAV improperly encoded in AAC's native channel order

+@example

+avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav

+@end example

+

 @section join

 Join multiple input streams into one multi-channel stream.

@@ -31,6 +31,7 @@ OBJS-$(CONFIG_AMIX_FILTER)                   += af_amix.o

 OBJS-$(CONFIG_ANULL_FILTER)                  += af_anull.o

 OBJS-$(CONFIG_ASPLIT_FILTER)                 += split.o

 OBJS-$(CONFIG_ASYNCTS_FILTER)                += af_asyncts.o

+OBJS-$(CONFIG_CHANNELMAP_FILTER)             += af_channelmap.o

 OBJS-$(CONFIG_CHANNELSPLIT_FILTER)           += af_channelsplit.o

 OBJS-$(CONFIG_JOIN_FILTER)                   += af_join.o

 OBJS-$(CONFIG_RESAMPLE_FILTER)               += af_resample.o

new file mode 100644

@@ -0,0 +1,402 @@

+/*

+ * Copyright (c) 2012 Google, Inc.

+ *

+ * This file is part of Libav.

+ *

+ * Libav is free software; you can redistribute it and/or

+ * modify it under the terms of the GNU Lesser General Public

+ * License as published by the Free Software Foundation; either

+ * version 2.1 of the License, or (at your option) any later version.

+ *

+ * Libav 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

+ * Lesser General Public License for more details.

+ *

+ * You should have received a copy of the GNU Lesser General Public

+ * License along with Libav; if not, write to the Free Software

+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

+ */

+

+/**

+ * @file

+ * audio channel mapping filter

+ */

+

+#include <ctype.h>

+

+#include "libavutil/audioconvert.h"

+#include "libavutil/avstring.h"

+#include "libavutil/mathematics.h"

+#include "libavutil/opt.h"

+#include "libavutil/samplefmt.h"

+

+#include "audio.h"

+#include "avfilter.h"

+#include "formats.h"

+#include "internal.h"

+

+struct ChannelMap {

+    uint64_t in_channel;

+    uint64_t out_channel;

+    int in_channel_idx;

+    int out_channel_idx;

+};

+

+enum MappingMode {

+    MAP_NONE,

+    MAP_ONE_INT,

+    MAP_ONE_STR,

+    MAP_PAIR_INT_INT,

+    MAP_PAIR_INT_STR,

+    MAP_PAIR_STR_INT,

+    MAP_PAIR_STR_STR

+};

+

+#define MAX_CH 64

+typedef struct ChannelMapContext {

+    const AVClass *class;

+    AVFilterChannelLayouts *channel_layouts;

+    char *mapping_str;

+    char *channel_layout_str;

+    uint64_t output_layout;

+    struct ChannelMap map[MAX_CH];

+    int nch;

+    enum MappingMode mode;

+} ChannelMapContext;

+

+#define OFFSET(x) offsetof(ChannelMapContext, x)

+#define A AV_OPT_FLAG_AUDIO_PARAM

+static const AVOption options[] = {

+    { "map", "A comma-separated list of input channel numbers in output order.",

+          OFFSET(mapping_str),        AV_OPT_TYPE_STRING, .flags = A },

+    { "channel_layout", "Output channel layout.",

+          OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, .flags = A },

+    { NULL },

+};

+

+static const AVClass channelmap_class = {

+    .class_name = "channel map filter",

+    .item_name  = av_default_item_name,

+    .option     = options,

+    .version    = LIBAVUTIL_VERSION_INT,

+};

+

+static char* split(char *message, char delim) {

+    char *next = strchr(message, delim);

+    if (next)

+      *next++ = '\0';

+    return next;

+}

+

+static int get_channel_idx(char **map, int *ch, char delim, int max_ch)

+{

+    char *next = split(*map, delim);

+    int len;

+    int n = 0;

+    if (!next && delim == '-')

+        return AVERROR(EINVAL);

+    len = strlen(*map);

+    sscanf(*map, "%d%n", ch, &n);

+    if (n != len)

+        return AVERROR(EINVAL);

+    if (*ch < 0 || *ch > max_ch)

+        return AVERROR(EINVAL);

+    *map = next;

+    return 0;

+}

+

+static int get_channel(char **map, uint64_t *ch, char delim)

+{

+    char *next = split(*map, delim);

+    if (!next && delim == '-')

+        return AVERROR(EINVAL);

+    *ch = av_get_channel_layout(*map);

+    if (av_get_channel_layout_nb_channels(*ch) != 1)

+        return AVERROR(EINVAL);

+    *map = next;

+    return 0;

+}

+

+static av_cold int channelmap_init(AVFilterContext *ctx, const char *args,

+                                   void *opaque)

+{

+    ChannelMapContext *s = ctx->priv;

+    int ret;

+    char *mapping;

+    enum mode;

+    int map_entries = 0;

+    char buf[256];

+    enum MappingMode mode;

+    uint64_t out_ch_mask = 0;

+    int i;

+

+    if (!args) {

+        av_log(ctx, AV_LOG_ERROR, "No parameters supplied.\n");

+        return AVERROR(EINVAL);

+    }

+

+    s->class = &channelmap_class;

+    av_opt_set_defaults(s);

+

+    if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {

+        av_log(ctx, AV_LOG_ERROR, "Error parsing options string '%s'.\n", args);

+        return ret;

+    }

+

+    mapping = s->mapping_str;

+

+    if (!mapping) {

+        mode = MAP_NONE;

+    } else {

+        char *dash = strchr(mapping, '-');

+        if (!dash) {  // short mapping

+            if (isdigit(*mapping))

+                mode = MAP_ONE_INT;

+            else

+                mode = MAP_ONE_STR;

+        } else if (isdigit(*mapping)) {

+            if (isdigit(*(dash+1)))

+                mode = MAP_PAIR_INT_INT;

+            else

+                mode = MAP_PAIR_INT_STR;

+        } else {

+            if (isdigit(*(dash+1)))

+                mode = MAP_PAIR_STR_INT;

+            else

+                mode = MAP_PAIR_STR_STR;

+        }

+    }

+

+    if (mode != MAP_NONE) {

+        char *comma = mapping;

+        map_entries = 1;

+        while ((comma = strchr(comma, ','))) {

+            if (*++comma)  // Allow trailing comma

+                map_entries++;

+        }

+    }

+

+    if (map_entries > MAX_CH) {

+        av_log(ctx, AV_LOG_ERROR, "Too many channels mapped: '%d'.\n", map_entries);

+        ret = AVERROR(EINVAL);

+        goto fail;

+    }

+

+    for (i = 0; i < map_entries; i++) {

+        int in_ch_idx = -1, out_ch_idx = -1;

+        uint64_t in_ch = 0, out_ch = 0;

+        static const char err[] = "Failed to parse channel map\n";

+        switch (mode) {

+        case MAP_ONE_INT:

+            if (get_channel_idx(&mapping, &in_ch_idx, ',', MAX_CH) < 0) {

+                ret = AVERROR(EINVAL);

+                av_log(ctx, AV_LOG_ERROR, err);

+                goto fail;

+            }

+            s->map[i].in_channel_idx  = in_ch_idx;

+            s->map[i].out_channel_idx = i;

+            break;

+        case MAP_ONE_STR:

+            if (!get_channel(&mapping, &in_ch, ',')) {

+                av_log(ctx, AV_LOG_ERROR, err);

+                ret = AVERROR(EINVAL);

+                goto fail;

+            }

+            s->map[i].in_channel      = in_ch;

+            s->map[i].out_channel_idx = i;

+            break;

+        case MAP_PAIR_INT_INT:

+            if (get_channel_idx(&mapping, &in_ch_idx, '-', MAX_CH) < 0 ||

+                get_channel_idx(&mapping, &out_ch_idx, ',', MAX_CH) < 0) {

+                av_log(ctx, AV_LOG_ERROR, err);

+                ret = AVERROR(EINVAL);

+                goto fail;

+            }

+            s->map[i].in_channel_idx  = in_ch_idx;

+            s->map[i].out_channel_idx = out_ch_idx;

+            break;

+        case MAP_PAIR_INT_STR:

+            if (get_channel_idx(&mapping, &in_ch_idx, '-', MAX_CH) < 0 ||

+                get_channel(&mapping, &out_ch, ',') < 0 ||

+                out_ch & out_ch_mask) {

+                av_log(ctx, AV_LOG_ERROR, err);

+                ret = AVERROR(EINVAL);

+                goto fail;

+            }

+            s->map[i].in_channel_idx  = in_ch_idx;

+            s->map[i].out_channel     = out_ch;

+            out_ch_mask |= out_ch;

+            break;

+        case MAP_PAIR_STR_INT:

+            if (get_channel(&mapping, &in_ch, '-') < 0 ||

+                get_channel_idx(&mapping, &out_ch_idx, ',', MAX_CH) < 0) {

+                av_log(ctx, AV_LOG_ERROR, err);

+                ret = AVERROR(EINVAL);

+                goto fail;

+            }

+            s->map[i].in_channel      = in_ch;

+            s->map[i].out_channel_idx = out_ch_idx;

+            break;

+        case MAP_PAIR_STR_STR:

+            if (get_channel(&mapping, &in_ch, '-') < 0 ||

+                get_channel(&mapping, &out_ch, ',') < 0 ||

+                out_ch & out_ch_mask) {

+                av_log(ctx, AV_LOG_ERROR, err);

+                ret = AVERROR(EINVAL);

+                goto fail;

+            }

+            s->map[i].in_channel = in_ch;

+            s->map[i].out_channel = out_ch;

+            out_ch_mask |= out_ch;

+            break;

+        }

+    }

+    s->mode          = mode;

+    s->nch           = map_entries;

+    s->output_layout = out_ch_mask ? out_ch_mask :

+                       av_get_default_channel_layout(map_entries);

+

+    if (s->channel_layout_str) {

+        uint64_t fmt;

+        if ((fmt = av_get_channel_layout(s->channel_layout_str)) == 0) {

+            av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout: '%s'.\n",

+                   s->channel_layout_str);

+            ret = AVERROR(EINVAL);

+            goto fail;

+        }

+        if (mode == MAP_NONE) {

+            int i;

+            s->nch = av_get_channel_layout_nb_channels(fmt);

+            for (i = 0; i < s->nch; i++) {

+                s->map[i].in_channel_idx  = i;

+                s->map[i].out_channel_idx = i;

+            }

+        } else if (out_ch_mask && out_ch_mask != fmt) {

+            av_get_channel_layout_string(buf, sizeof(buf), 0, out_ch_mask);

+            av_log(ctx, AV_LOG_ERROR,

+                   "Output channel layout '%s' does not match the list of channel mapped: '%s'.\n",

+                   s->channel_layout_str, buf);

+            ret = AVERROR(EINVAL);

+            goto fail;

+        } else if (s->nch != av_get_channel_layout_nb_channels(fmt)) {

+            av_log(ctx, AV_LOG_ERROR,

+                   "Output channel layout %s does not match the number of channels mapped %d.\n",

+                   s->channel_layout_str, s->nch);

+            ret = AVERROR(EINVAL);

+            goto fail;

+        }

+        s->output_layout = fmt;

+    }

+    ff_add_channel_layout(&s->channel_layouts, s->output_layout);

+

+    if (mode == MAP_PAIR_INT_STR || mode == MAP_PAIR_STR_STR) {

+        for (i = 0; i < s->nch; i++) {

+            s->map[i].out_channel_idx = av_get_channel_layout_channel_index(

+                s->output_layout, s->map[i].out_channel);

+        }

+    }

+

+fail:

+    av_opt_free(s);

+    return ret;

+}

+

+static int channelmap_query_formats(AVFilterContext *ctx)

+{

+    ChannelMapContext *s = ctx->priv;

+

+    ff_set_common_formats(ctx, ff_planar_sample_fmts());

+    ff_set_common_samplerates(ctx, ff_all_samplerates());

+    ff_channel_layouts_ref(ff_all_channel_layouts(), &ctx->inputs[0]->out_channel_layouts);

+    ff_channel_layouts_ref(s->channel_layouts,       &ctx->outputs[0]->in_channel_layouts);

+

+    return 0;

+}

+

+static void channelmap_filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)

+{

+    AVFilterContext  *ctx = inlink->dst;

+    AVFilterLink *outlink = ctx->outputs[0];

+    const ChannelMapContext *s = ctx->priv;

+    const int nch_in = av_get_channel_layout_nb_channels(inlink->channel_layout);

+    const int nch_out = s->nch;

+    int ch;

+    uint8_t *source_planes[MAX_CH];

+

+    memcpy(source_planes, buf->extended_data,

+           nch_in * sizeof(source_planes[0]));

+

+    if (nch_out > nch_in) {

+        if (nch_out > FF_ARRAY_ELEMS(buf->data)) {

+            uint8_t **new_extended_data =

+                av_mallocz(nch_out * sizeof(*buf->extended_data));

+            if (!new_extended_data)

+                return;

+            if (buf->extended_data == buf->data) {

+                buf->extended_data = new_extended_data;

+            } else {

+                buf->extended_data = new_extended_data;

+                av_free(buf->extended_data);

+            }

+        } else if (buf->extended_data != buf->data) {

+            av_free(buf->extended_data);

+            buf->extended_data = buf->data;

+        }

+    }

+

+    for (ch = 0; ch < nch_out; ch++) {

+        buf->extended_data[s->map[ch].out_channel_idx] =

+            source_planes[s->map[ch].in_channel_idx];

+    }

+

+    if (buf->data != buf->extended_data)

+        memcpy(buf->data, buf->extended_data,

+           FFMIN(FF_ARRAY_ELEMS(buf->data), nch_out) * sizeof(buf->data[0]));

+

+    ff_filter_samples(outlink, buf);

+}

+

+static int channelmap_config_input(AVFilterLink *inlink)

+{

+    AVFilterContext *ctx = inlink->dst;

+    ChannelMapContext *s = ctx->priv;

+    int i, err = 0;

+    const char *channel_name;

+    char layout_name[256];

+

+    if (s->mode == MAP_PAIR_STR_INT || s->mode == MAP_PAIR_STR_STR) {

+        for (i = 0; i < s->nch; i++) {

+            s->map[i].in_channel_idx = av_get_channel_layout_channel_index(

+                inlink->channel_layout, s->map[i].in_channel);

+            if (s->map[i].in_channel_idx < 0) {

+                channel_name = av_get_channel_name(s->map[i].in_channel);

+                av_get_channel_layout_string(layout_name, sizeof(layout_name),

+                                             0, inlink->channel_layout);

+                av_log(ctx, AV_LOG_ERROR,

+                       "input channel '%s' not available from input layout '%s'\n",

+                       channel_name, layout_name);

+                err = AVERROR(EINVAL);

+            }

+        }

+    }

+

+    return err;

+}

+

+AVFilter avfilter_af_channelmap = {

+    .name          = "channelmap",

+    .description   = NULL_IF_CONFIG_SMALL("Remap audio channels."),

+    .init          = channelmap_init,

+    .query_formats = channelmap_query_formats,

+    .priv_size     = sizeof(ChannelMapContext),

+

+    .inputs        = (AVFilterPad[]) {{ .name            = "default",

+                                        .type            = AVMEDIA_TYPE_AUDIO,

+                                        .filter_samples  = channelmap_filter_samples,

+                                        .config_props    = channelmap_config_input },

+                                      { .name = NULL }},

+    .outputs       = (AVFilterPad[]) {{ .name            = "default",

+                                        .type            = AVMEDIA_TYPE_AUDIO },

+                                      { .name = NULL }},

+};

@@ -40,6 +40,7 @@ void avfilter_register_all(void)

     REGISTER_FILTER (ANULL,       anull,       af);

     REGISTER_FILTER (ASPLIT,      asplit,      af);

     REGISTER_FILTER (ASYNCTS,     asyncts,     af);

+    REGISTER_FILTER (CHANNELMAP,  channelmap,  af);

     REGISTER_FILTER (CHANNELSPLIT,channelsplit,af);

     REGISTER_FILTER (JOIN,        join,        af);

     REGISTER_FILTER (RESAMPLE,    resample,    af);