/*
  * Filter layer - format negotiation

  * Copyright (c) 2007 Bobby Bingham

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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.
  *
  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #include "libavutil/avassert.h"

 #include "libavutil/channel_layout.h"

 #include "libavutil/common.h"

 #include "libavutil/eval.h"

 #include "libavutil/pixdesc.h"

 #include "libavutil/parseutils.h"

 #include "avfilter.h"

 #include "internal.h"

 #include "formats.h"

 #define KNOWN(l) (!FF_LAYOUT2COUNT(l)) /* for readability */
 

 /**
  * Add all refs from a to ret and destroy a.
  */

 #define MERGE_REF(ret, a, fmts, type, fail)                                \
 do {                                                                       \
     type ***tmp;                                                           \
     int i;                                                                 \
                                                                            \

     if (!(tmp = av_realloc_array(ret->refs, ret->refcount + a->refcount,   \
                                  sizeof(*tmp))))                           \

         goto fail;                                                         \
     ret->refs = tmp;                                                       \
                                                                            \
     for (i = 0; i < a->refcount; i ++) {                                   \
         ret->refs[ret->refcount] = a->refs[i];                             \
         *ret->refs[ret->refcount++] = ret;                                 \
     }                                                                      \
                                                                            \
     av_freep(&a->refs);                                                    \
     av_freep(&a->fmts);                                                    \
     av_freep(&a);                                                          \
 } while (0)

 /**
  * Add all formats common for a and b to ret, copy the refs and destroy
  * a and b.
  */
 #define MERGE_FORMATS(ret, a, b, fmts, nb, type, fail)                          \
 do {                                                                            \
     int i, j, k = 0, count = FFMIN(a->nb, b->nb);                               \
                                                                                 \
     if (!(ret = av_mallocz(sizeof(*ret))))                                      \
         goto fail;                                                              \
                                                                                 \
     if (count) {                                                                \

         if (!(ret->fmts = av_malloc_array(count, sizeof(*ret->fmts))))          \

             goto fail;                                                          \
         for (i = 0; i < a->nb; i++)                                             \
             for (j = 0; j < b->nb; j++)                                         \

                 if (a->fmts[i] == b->fmts[j]) {                                 \
                     if(k >= FFMIN(a->nb, b->nb)){                               \

                         av_log(NULL, AV_LOG_ERROR, "Duplicate formats in avfilter_merge_formats() detected\n"); \

                         av_free(ret->fmts);                                     \
                         av_free(ret);                                           \
                         return NULL;                                            \
                     }                                                           \

                     ret->fmts[k++] = a->fmts[i];                                \

                 }                                                               \

     }                                                                           \

     ret->nb = k;                                                                \

     /* check that there was at least one common format */                       \
     if (!ret->nb)                                                               \
         goto fail;                                                              \
                                                                                 \
     MERGE_REF(ret, a, fmts, type, fail);                                        \
     MERGE_REF(ret, b, fmts, type, fail);                                        \
 } while (0)

 AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b,
                                   enum AVMediaType type)

 {

     AVFilterFormats *ret = NULL;

     int i, j;
     int alpha1=0, alpha2=0;
     int chroma1=0, chroma2=0;

     if (a == b)
         return a;

     /* Do not lose chroma or alpha in merging.
        It happens if both lists have formats with chroma (resp. alpha), but
        the only formats in common do not have it (e.g. YUV+gray vs.
        RGB+gray): in that case, the merging would select the gray format,
        possibly causing a lossy conversion elsewhere in the graph.
        To avoid that, pretend that there are no common formats to force the
        insertion of a conversion filter. */
     if (type == AVMEDIA_TYPE_VIDEO)

         for (i = 0; i < a->nb_formats; i++)
             for (j = 0; j < b->nb_formats; j++) {

                 const AVPixFmtDescriptor *adesc = av_pix_fmt_desc_get(a->formats[i]);
                 const AVPixFmtDescriptor *bdesc = av_pix_fmt_desc_get(b->formats[j]);

                 alpha2 |= adesc->flags & bdesc->flags & AV_PIX_FMT_FLAG_ALPHA;

                 chroma2|= adesc->nb_components > 1 && bdesc->nb_components > 1;
                 if (a->formats[i] == b->formats[j]) {

                     alpha1 |= adesc->flags & AV_PIX_FMT_FLAG_ALPHA;

                     chroma1|= adesc->nb_components > 1;
                 }

             }
 
     // If chroma or alpha can be lost through merging then do not merge
     if (alpha2 > alpha1 || chroma2 > chroma1)
         return NULL;
 

     MERGE_FORMATS(ret, a, b, formats, nb_formats, AVFilterFormats, fail);

     return ret;
 fail:
     if (ret) {
         av_freep(&ret->refs);
         av_freep(&ret->formats);

     }

     av_freep(&ret);
     return NULL;
 }
 
 AVFilterFormats *ff_merge_samplerates(AVFilterFormats *a,
                                       AVFilterFormats *b)
 {
     AVFilterFormats *ret = NULL;

     if (a == b) return a;

     if (a->nb_formats && b->nb_formats) {
         MERGE_FORMATS(ret, a, b, formats, nb_formats, AVFilterFormats, fail);
     } else if (a->nb_formats) {

         MERGE_REF(a, b, formats, AVFilterFormats, fail);
         ret = a;
     } else {
         MERGE_REF(b, a, formats, AVFilterFormats, fail);
         ret = b;

     }
 
     return ret;

 fail:
     if (ret) {
         av_freep(&ret->refs);
         av_freep(&ret->formats);
     }
     av_freep(&ret);
     return NULL;
 }

 AVFilterChannelLayouts *ff_merge_channel_layouts(AVFilterChannelLayouts *a,
                                                  AVFilterChannelLayouts *b)
 {
     AVFilterChannelLayouts *ret = NULL;

     unsigned a_all = a->all_layouts + a->all_counts;
     unsigned b_all = b->all_layouts + b->all_counts;
     int ret_max, ret_nb = 0, i, j, round;

 
     if (a == b) return a;
 

     /* Put the most generic set in a, to avoid doing everything twice */
     if (a_all < b_all) {
         FFSWAP(AVFilterChannelLayouts *, a, b);
         FFSWAP(unsigned, a_all, b_all);
     }
     if (a_all) {
         if (a_all == 1 && !b_all) {
             /* keep only known layouts in b; works also for b_all = 1 */
             for (i = j = 0; i < b->nb_channel_layouts; i++)
                 if (KNOWN(b->channel_layouts[i]))
                     b->channel_layouts[j++] = b->channel_layouts[i];

             /* Not optimal: the unknown layouts of b may become known after
                another merge. */
             if (!j)
                 return NULL;

             b->nb_channel_layouts = j;
         }

         MERGE_REF(b, a, channel_layouts, AVFilterChannelLayouts, fail);

         return b;
     }
 
     ret_max = a->nb_channel_layouts + b->nb_channel_layouts;
     if (!(ret = av_mallocz(sizeof(*ret))) ||

         !(ret->channel_layouts = av_malloc_array(ret_max,
                                                  sizeof(*ret->channel_layouts))))

         goto fail;
 
     /* a[known] intersect b[known] */
     for (i = 0; i < a->nb_channel_layouts; i++) {
         if (!KNOWN(a->channel_layouts[i]))
             continue;
         for (j = 0; j < b->nb_channel_layouts; j++) {
             if (a->channel_layouts[i] == b->channel_layouts[j]) {
                 ret->channel_layouts[ret_nb++] = a->channel_layouts[i];
                 a->channel_layouts[i] = b->channel_layouts[j] = 0;
             }
         }
     }
     /* 1st round: a[known] intersect b[generic]
        2nd round: a[generic] intersect b[known] */
     for (round = 0; round < 2; round++) {
         for (i = 0; i < a->nb_channel_layouts; i++) {
             uint64_t fmt = a->channel_layouts[i], bfmt;
             if (!fmt || !KNOWN(fmt))
                 continue;
             bfmt = FF_COUNT2LAYOUT(av_get_channel_layout_nb_channels(fmt));
             for (j = 0; j < b->nb_channel_layouts; j++)
                 if (b->channel_layouts[j] == bfmt)
                     ret->channel_layouts[ret_nb++] = a->channel_layouts[i];
         }
         /* 1st round: swap to prepare 2nd round; 2nd round: put it back */
         FFSWAP(AVFilterChannelLayouts *, a, b);
     }
     /* a[generic] intersect b[generic] */
     for (i = 0; i < a->nb_channel_layouts; i++) {
         if (KNOWN(a->channel_layouts[i]))
             continue;
         for (j = 0; j < b->nb_channel_layouts; j++)
             if (a->channel_layouts[i] == b->channel_layouts[j])
                 ret->channel_layouts[ret_nb++] = a->channel_layouts[i];

     }

     ret->nb_channel_layouts = ret_nb;
     if (!ret->nb_channel_layouts)
         goto fail;
     MERGE_REF(ret, a, channel_layouts, AVFilterChannelLayouts, fail);
     MERGE_REF(ret, b, channel_layouts, AVFilterChannelLayouts, fail);

     return ret;

 fail:
     if (ret) {
         av_freep(&ret->refs);
         av_freep(&ret->channel_layouts);
     }
     av_freep(&ret);
     return NULL;

 }
 

 int ff_fmt_is_in(int fmt, const int *fmts)
 {
     const int *p;
 
     for (p = fmts; *p != -1; p++) {
         if (fmt == *p)
             return 1;
     }
     return 0;
 }
 

 #define MAKE_FORMAT_LIST(type, field, count_field)                      \
     type *formats;                                                      \

     int count = 0;                                                      \
     if (fmts)                                                           \
         for (count = 0; fmts[count] != -1; count++)                     \
             ;                                                           \

     formats = av_mallocz(sizeof(*formats));                             \

     if (!formats)                                                       \
         return NULL;                                                    \

     formats->count_field = count;                                       \

     if (count) {                                                        \

         formats->field = av_malloc_array(count, sizeof(*formats->field));      \

         if (!formats->field) {                                          \

             av_freep(&formats);                                         \

             return NULL;                                                \
         }                                                               \
     }
 

 AVFilterFormats *ff_make_format_list(const int *fmts)

 {

     MAKE_FORMAT_LIST(AVFilterFormats, formats, nb_formats);

     while (count--)
         formats->formats[count] = fmts[count];

     return formats;
 }

 
 AVFilterChannelLayouts *ff_make_formatu64_list(const uint64_t *fmts)
 {
     MAKE_FORMAT_LIST(AVFilterChannelLayouts,
                      channel_layouts, nb_channel_layouts);
     if (count)
         memcpy(formats->channel_layouts, fmts,
                sizeof(*formats->channel_layouts) * count);
 
     return formats;
 }

 AVFilterChannelLayouts *avfilter_make_format64_list(const int64_t *fmts)

 {

     MAKE_FORMAT_LIST(AVFilterChannelLayouts,
                      channel_layouts, nb_channel_layouts);

     if (count)

         memcpy(formats->channel_layouts, fmts,
                sizeof(*formats->channel_layouts) * count);

     return formats;

 }
 

 #define ADD_FORMAT(f, fmt, unref_fn, type, list, nb)        \

 do {                                                        \
     type *fmts;                                             \

     void *oldf = *f;                                        \

                                                             \

     if (!(*f) && !(*f = av_mallocz(sizeof(**f)))) {         \
         unref_fn(f);                                        \

         return AVERROR(ENOMEM);                             \

     }                                                       \

                                                             \

     fmts = av_realloc_array((*f)->list, (*f)->nb + 1,       \
                             sizeof(*(*f)->list));           \

     if (!fmts) {                                            \

         unref_fn(f);                                        \

         if (!oldf)                                          \
             av_freep(f);                                    \

         return AVERROR(ENOMEM);                             \

     }                                                       \

                                                             \
     (*f)->list = fmts;                                      \
     (*f)->list[(*f)->nb++] = fmt;                           \
 } while (0)
 

 int ff_add_format(AVFilterFormats **avff, int64_t fmt)

 {

     ADD_FORMAT(avff, fmt, ff_formats_unref, int, formats, nb_formats);

     return 0;

 }

 int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout)
 {

     av_assert1(!(*l && (*l)->all_layouts));

     ADD_FORMAT(l, channel_layout, ff_channel_layouts_unref, uint64_t, channel_layouts, nb_channel_layouts);

     return 0;

 }
 

 AVFilterFormats *ff_all_formats(enum AVMediaType type)

 {

     AVFilterFormats *ret = NULL;

     if (type == AVMEDIA_TYPE_VIDEO) {
         const AVPixFmtDescriptor *desc = NULL;
         while ((desc = av_pix_fmt_desc_next(desc))) {

             if (ff_add_format(&ret, av_pix_fmt_desc_get_id(desc)) < 0)
                 return NULL;

         }
     } else if (type == AVMEDIA_TYPE_AUDIO) {
         enum AVSampleFormat fmt = 0;
         while (av_get_sample_fmt_name(fmt)) {

             if (ff_add_format(&ret, fmt) < 0)
                 return NULL;

             fmt++;
         }

     }

 
     return ret;

 }
 

 const int64_t avfilter_all_channel_layouts[] = {

 #include "all_channel_layouts.inc"

     -1
 };
 

 // AVFilterFormats *avfilter_make_all_channel_layouts(void)
 // {
 //     return avfilter_make_format64_list(avfilter_all_channel_layouts);
 // }

 AVFilterFormats *ff_planar_sample_fmts(void)
 {
     AVFilterFormats *ret = NULL;
     int fmt;
 

     for (fmt = 0; av_get_bytes_per_sample(fmt)>0; fmt++)

         if (av_sample_fmt_is_planar(fmt))

             if (ff_add_format(&ret, fmt) < 0)
                 return NULL;

 
     return ret;
 }
 

 AVFilterFormats *ff_all_samplerates(void)

 {

     AVFilterFormats *ret = av_mallocz(sizeof(*ret));
     return ret;

 }
 

 AVFilterChannelLayouts *ff_all_channel_layouts(void)

 {

     AVFilterChannelLayouts *ret = av_mallocz(sizeof(*ret));

     if (!ret)
         return NULL;
     ret->all_layouts = 1;

     return ret;

 }
 

 AVFilterChannelLayouts *ff_all_channel_counts(void)
 {
     AVFilterChannelLayouts *ret = av_mallocz(sizeof(*ret));
     if (!ret)
         return NULL;
     ret->all_layouts = ret->all_counts = 1;
     return ret;
 }
 

 #define FORMATS_REF(f, ref, unref_fn)                                           \

     void *tmp;                                                                  \
                                                                                 \

     if (!f || !ref)                                                             \
         return AVERROR(ENOMEM);                                                 \

                                                                                 \
     tmp = av_realloc_array(f->refs, sizeof(*f->refs), f->refcount + 1);         \

     if (!tmp) {                                                                 \
         unref_fn(&f);                                                           \

         return AVERROR(ENOMEM);                                                 \

     }                                                                           \

     f->refs = tmp;                                                              \
     f->refs[f->refcount++] = ref;                                               \
     *ref = f;                                                                   \
     return 0
 
 int ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)

 {

     FORMATS_REF(f, ref, ff_channel_layouts_unref);

 }

 int ff_formats_ref(AVFilterFormats *f, AVFilterFormats **ref)

 {

     FORMATS_REF(f, ref, ff_formats_unref);

 }

 #define FIND_REF_INDEX(ref, idx)            \
 do {                                        \
     int i;                                  \
     for (i = 0; i < (*ref)->refcount; i ++) \
         if((*ref)->refs[i] == ref) {        \
             idx = i;                        \
             break;                          \
         }                                   \
 } while (0)
 
 #define FORMATS_UNREF(ref, list)                                   \
 do {                                                               \
     int idx = -1;                                                  \
                                                                    \

     if (!*ref || !(*ref)->refs)                                    \

         return;                                                    \
                                                                    \
     FIND_REF_INDEX(ref, idx);                                      \
                                                                    \
     if (idx >= 0)                                                  \
         memmove((*ref)->refs + idx, (*ref)->refs + idx + 1,        \
             sizeof(*(*ref)->refs) * ((*ref)->refcount - idx - 1)); \
                                                                    \
     if(!--(*ref)->refcount) {                                      \
         av_free((*ref)->list);                                     \
         av_free((*ref)->refs);                                     \
         av_free(*ref);                                             \
     }                                                              \
     *ref = NULL;                                                   \
 } while (0)

 void ff_formats_unref(AVFilterFormats **ref)

 {
     FORMATS_UNREF(ref, formats);
 }

 void ff_channel_layouts_unref(AVFilterChannelLayouts **ref)
 {
     FORMATS_UNREF(ref, channel_layouts);
 }

 #define FORMATS_CHANGEREF(oldref, newref)       \
 do {                                            \
     int idx = -1;                               \
                                                 \
     FIND_REF_INDEX(oldref, idx);                \
                                                 \
     if (idx >= 0) {                             \
         (*oldref)->refs[idx] = newref;          \
         *newref = *oldref;                      \
         *oldref = NULL;                         \
     }                                           \
 } while (0)
 
 void ff_channel_layouts_changeref(AVFilterChannelLayouts **oldref,
                                   AVFilterChannelLayouts **newref)
 {
     FORMATS_CHANGEREF(oldref, newref);

 }
 

 void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref)

 {

     FORMATS_CHANGEREF(oldref, newref);

 }

 #define SET_COMMON_FORMATS(ctx, fmts, in_fmts, out_fmts, ref_fn, unref_fn, list) \

     int count = 0, i;                                               \
                                                                     \

     if (!fmts)                                                      \

         return AVERROR(ENOMEM);                                     \

                                                                     \

     for (i = 0; i < ctx->nb_inputs; i++) {                          \

         if (ctx->inputs[i] && !ctx->inputs[i]->out_fmts) {          \

             int ret = ref_fn(fmts, &ctx->inputs[i]->out_fmts);      \
             if (ret < 0) {                                          \
                 unref_fn(&fmts);                                    \

                 av_freep(&fmts->list);                              \
                 av_freep(&fmts);                                    \

                 return ret;                                         \

             }                                                       \

             count++;                                                \
         }                                                           \
     }                                                               \

     for (i = 0; i < ctx->nb_outputs; i++) {                         \

         if (ctx->outputs[i] && !ctx->outputs[i]->in_fmts) {         \

             int ret = ref_fn(fmts, &ctx->outputs[i]->in_fmts);      \
             if (ret < 0) {                                          \
                 unref_fn(&fmts);                                    \

                 av_freep(&fmts->list);                              \
                 av_freep(&fmts);                                    \

                 return ret;                                         \

             }                                                       \

             count++;                                                \
         }                                                           \
     }                                                               \
                                                                     \
     if (!count) {                                                   \
         av_freep(&fmts->list);                                      \
         av_freep(&fmts->refs);                                      \
         av_freep(&fmts);                                            \
     }                                                               \

                                                                     \
     return 0;

 int ff_set_common_channel_layouts(AVFilterContext *ctx,
                                   AVFilterChannelLayouts *layouts)

 {
     SET_COMMON_FORMATS(ctx, layouts, in_channel_layouts, out_channel_layouts,

                        ff_channel_layouts_ref, ff_channel_layouts_unref, channel_layouts);

 }
 

 int ff_set_common_samplerates(AVFilterContext *ctx,
                               AVFilterFormats *samplerates)

 {
     SET_COMMON_FORMATS(ctx, samplerates, in_samplerates, out_samplerates,

                        ff_formats_ref, ff_formats_unref, formats);

 }
 
 /**
  * A helper for query_formats() which sets all links to the same list of
  * formats. If there are no links hooked to this filter, the list of formats is
  * freed.
  */

 int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)

 {
     SET_COMMON_FORMATS(ctx, formats, in_formats, out_formats,

                        ff_formats_ref, ff_formats_unref, formats);

 }

 static int default_query_formats_common(AVFilterContext *ctx,
                                         AVFilterChannelLayouts *(layouts)(void))

 {

     int ret;

     enum AVMediaType type = ctx->inputs  && ctx->inputs [0] ? ctx->inputs [0]->type :
                             ctx->outputs && ctx->outputs[0] ? ctx->outputs[0]->type :
                             AVMEDIA_TYPE_VIDEO;
 

     ret = ff_set_common_formats(ctx, ff_all_formats(type));
     if (ret < 0)
         return ret;

     if (type == AVMEDIA_TYPE_AUDIO) {

         ret = ff_set_common_channel_layouts(ctx, layouts());
         if (ret < 0)
             return ret;
         ret = ff_set_common_samplerates(ctx, ff_all_samplerates());
         if (ret < 0)
             return ret;

     }

 
     return 0;

 }
 

 int ff_default_query_formats(AVFilterContext *ctx)
 {

     return default_query_formats_common(ctx, ff_all_channel_counts);

 }
 

 int ff_query_formats_all_layouts(AVFilterContext *ctx)

 {

     return default_query_formats_common(ctx, ff_all_channel_layouts);

 }
 

 /* internal functions for parsing audio format arguments */
 

 int ff_parse_pixel_format(enum AVPixelFormat *ret, const char *arg, void *log_ctx)

 {
     char *tail;
     int pix_fmt = av_get_pix_fmt(arg);

     if (pix_fmt == AV_PIX_FMT_NONE) {

         pix_fmt = strtol(arg, &tail, 0);

         if (*tail || !av_pix_fmt_desc_get(pix_fmt)) {

             av_log(log_ctx, AV_LOG_ERROR, "Invalid pixel format '%s'\n", arg);
             return AVERROR(EINVAL);
         }
     }
     *ret = pix_fmt;
     return 0;
 }
 

 int ff_parse_sample_format(int *ret, const char *arg, void *log_ctx)
 {
     char *tail;
     int sfmt = av_get_sample_fmt(arg);
     if (sfmt == AV_SAMPLE_FMT_NONE) {
         sfmt = strtol(arg, &tail, 0);

         if (*tail || av_get_bytes_per_sample(sfmt)<=0) {

             av_log(log_ctx, AV_LOG_ERROR, "Invalid sample format '%s'\n", arg);
             return AVERROR(EINVAL);
         }
     }
     *ret = sfmt;
     return 0;
 }
 

 int ff_parse_time_base(AVRational *ret, const char *arg, void *log_ctx)
 {
     AVRational r;
     if(av_parse_ratio(&r, arg, INT_MAX, 0, log_ctx) < 0 ||r.num<=0  ||r.den<=0) {
         av_log(log_ctx, AV_LOG_ERROR, "Invalid time base '%s'\n", arg);
         return AVERROR(EINVAL);
     }
     *ret = r;
     return 0;
 }
 

 int ff_parse_sample_rate(int *ret, const char *arg, void *log_ctx)

 {
     char *tail;
     double srate = av_strtod(arg, &tail);

     if (*tail || srate < 1 || (int)srate != srate || srate > INT_MAX) {

         av_log(log_ctx, AV_LOG_ERROR, "Invalid sample rate '%s'\n", arg);
         return AVERROR(EINVAL);
     }
     *ret = srate;
     return 0;
 }
 

 int ff_parse_channel_layout(int64_t *ret, int *nret, const char *arg,
                             void *log_ctx)

 {
     char *tail;

     int64_t chlayout;

     int nb_channels;
 
     if (av_get_extended_channel_layout(arg, &chlayout, &nb_channels) < 0) {
         /* [TEMPORARY 2016-12 -> 2017-12]*/
         nb_channels = strtol(arg, &tail, 10);
         if (!errno && *tail == 'c' && *(tail + 1) == '\0' && nb_channels > 0 && nb_channels < 64) {
             chlayout = 0;
             av_log(log_ctx, AV_LOG_WARNING, "Deprecated channel count specification '%s'. This will stop working in releases made in 2018 and after.\n", arg);
         } else {

             av_log(log_ctx, AV_LOG_ERROR, "Invalid channel layout '%s'\n", arg);
             return AVERROR(EINVAL);
         }

     }
     if (!chlayout && !nret) {
         av_log(log_ctx, AV_LOG_ERROR, "Unknown channel layout '%s' is not supported.\n", arg);
         return AVERROR(EINVAL);

     }
     *ret = chlayout;

     if (nret)

         *nret = nb_channels;
 

     return 0;
 }