avfilter: add stereowiden filter
[ffmpeg.git] / libavfilter / formats.c
index 3ec6839..8758b3d 100644 (file)
@@ -2,28 +2,35 @@
  * Filter layer - format negotiation
  * Copyright (c) 2007 Bobby Bingham
  *
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * 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.
  *
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * 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.
  */
@@ -32,8 +39,8 @@ do {                                                                       \
     type ***tmp;                                                           \
     int i;                                                                 \
                                                                            \
-    if (!(tmp = av_realloc(ret->refs,                                      \
-                           sizeof(*tmp) * (ret->refcount + a->refcount)))) \
+    if (!(tmp = av_realloc_array(ret->refs, ret->refcount + a->refcount,   \
+                                 sizeof(*tmp))))                           \
         goto fail;                                                         \
     ret->refs = tmp;                                                       \
                                                                            \
@@ -59,15 +66,21 @@ do {
         goto fail;                                                              \
                                                                                 \
     if (count) {                                                                \
-        if (!(ret->fmts = av_malloc(sizeof(*ret->fmts) * 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 (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;                                                            \
+                }                                                               \
     }                                                                           \
+    ret->nb = k;                                                                \
     /* check that there was at least one common format */                       \
     if (!ret->nb)                                                               \
         goto fail;                                                              \
@@ -76,14 +89,42 @@ do {
     MERGE_REF(ret, b, fmts, type, fail);                                        \
 } while (0)
 
-AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b)
+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;
 
-    MERGE_FORMATS(ret, a, b, formats, format_count, AVFilterFormats, fail);
+    /* 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:
@@ -102,9 +143,9 @@ AVFilterFormats *ff_merge_samplerates(AVFilterFormats *a,
 
     if (a == b) return a;
 
-    if (a->format_count && b->format_count) {
-        MERGE_FORMATS(ret, a, b, formats, format_count, AVFilterFormats, fail);
-    } else if (a->format_count) {
+    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 {
@@ -126,21 +167,81 @@ 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;
 
-    if (a->nb_channel_layouts && b->nb_channel_layouts) {
-        MERGE_FORMATS(ret, a, b, channel_layouts, nb_channel_layouts,
-                      AVFilterChannelLayouts, fail);
-    } else if (a->nb_channel_layouts) {
-        MERGE_REF(a, b, channel_layouts, AVFilterChannelLayouts, fail);
-        ret = a;
-    } else {
+    /* 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);
-        ret = b;
+        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);
@@ -154,26 +255,47 @@ int ff_fmt_is_in(int fmt, const int *fmts)
 {
     const int *p;
 
-    for (p = fmts; *p != PIX_FMT_NONE; 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)
 {
-    AVFilterFormats *formats;
-    int count;
+    MAKE_FORMAT_LIST(AVFilterFormats, formats, nb_formats);
+    while (count--)
+        formats->formats[count] = fmts[count];
 
-    for (count = 0; fmts[count] != -1; count++)
-        ;
+    return formats;
+}
 
-    formats               = av_mallocz(sizeof(*formats));
+AVFilterChannelLayouts *avfilter_make_format64_list(const int64_t *fmts)
+{
+    MAKE_FORMAT_LIST(AVFilterChannelLayouts,
+                     channel_layouts, nb_channel_layouts);
     if (count)
-        formats->formats  = av_malloc(sizeof(*formats->formats) * count);
-    formats->format_count = count;
-    memcpy(formats->formats, fmts, sizeof(*formats->formats) * count);
+        memcpy(formats->channel_layouts, fmts,
+               sizeof(*formats->channel_layouts) * count);
 
     return formats;
 }
@@ -181,51 +303,73 @@ AVFilterFormats *ff_make_format_list(const int *fmts)
 #define ADD_FORMAT(f, fmt, type, list, nb)                  \
 do {                                                        \
     type *fmts;                                             \
+    void *oldf = *f;                                        \
                                                             \
     if (!(*f) && !(*f = av_mallocz(sizeof(**f))))           \
         return AVERROR(ENOMEM);                             \
                                                             \
-    fmts = av_realloc((*f)->list,                           \
-                      sizeof(*(*f)->list) * ((*f)->nb + 1));\
-    if (!fmts)                                              \
+    fmts = av_realloc_array((*f)->list, (*f)->nb + 1,       \
+                            sizeof(*(*f)->list));           \
+    if (!fmts) {                                            \
+        if (!oldf)                                          \
+            av_freep(f);                                    \
         return AVERROR(ENOMEM);                             \
+    }                                                       \
                                                             \
     (*f)->list = fmts;                                      \
     (*f)->list[(*f)->nb++] = fmt;                           \
-    return 0;                                               \
 } while (0)
 
-int ff_add_format(AVFilterFormats **avff, int fmt)
+int ff_add_format(AVFilterFormats **avff, int64_t fmt)
 {
-    ADD_FORMAT(avff, fmt, int, formats, format_count);
+    ADD_FORMAT(avff, fmt, 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, uint64_t, channel_layouts, nb_channel_layouts);
+    return 0;
 }
 
 AVFilterFormats *ff_all_formats(enum AVMediaType type)
 {
     AVFilterFormats *ret = NULL;
-    int fmt;
-    int num_formats = type == AVMEDIA_TYPE_VIDEO ? PIX_FMT_NB    :
-                      type == AVMEDIA_TYPE_AUDIO ? AV_SAMPLE_FMT_NB : 0;
 
-    for (fmt = 0; fmt < num_formats; fmt++)
-        if ((type != AVMEDIA_TYPE_VIDEO) ||
-            (type == AVMEDIA_TYPE_VIDEO && !(av_pix_fmt_descriptors[fmt].flags & PIX_FMT_HWACCEL)))
+    if (type == AVMEDIA_TYPE_VIDEO) {
+        const AVPixFmtDescriptor *desc = NULL;
+        while ((desc = av_pix_fmt_desc_next(desc))) {
+            if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
+                ff_add_format(&ret, av_pix_fmt_desc_get_id(desc));
+        }
+    } else if (type == AVMEDIA_TYPE_AUDIO) {
+        enum AVSampleFormat fmt = 0;
+        while (av_get_sample_fmt_name(fmt)) {
             ff_add_format(&ret, fmt);
+            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; fmt < AV_SAMPLE_FMT_NB; fmt++)
+    for (fmt = 0; av_get_bytes_per_sample(fmt)>0; fmt++)
         if (av_sample_fmt_is_planar(fmt))
             ff_add_format(&ret, fmt);
 
@@ -241,22 +385,41 @@ AVFilterFormats *ff_all_samplerates(void)
 AVFilterChannelLayouts *ff_all_channel_layouts(void)
 {
     AVFilterChannelLayouts *ret = av_mallocz(sizeof(*ret));
+    if (!ret)
+        return NULL;
+    ret->all_layouts = 1;
     return ret;
 }
 
-#define FORMATS_REF(f, ref)                                          \
-do {                                                                 \
-    *ref = f;                                                        \
-    f->refs = av_realloc(f->refs, sizeof(*f->refs) * ++f->refcount); \
-    f->refs[f->refcount-1] = ref;                                    \
-} while (0)
+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;
+}
 
-void ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
+#define FORMATS_REF(f, ref)                                                     \
+    void *tmp;                                                                  \
+                                                                                \
+    if (!ref)                                                                   \
+        return AVERROR_BUG;                                                     \
+                                                                                \
+    tmp = av_realloc_array(f->refs, sizeof(*f->refs), f->refcount + 1);         \
+    if (!tmp)                                                                   \
+        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);
 }
 
-void ff_formats_ref(AVFilterFormats *f, AVFilterFormats **ref)
+int ff_formats_ref(AVFilterFormats *f, AVFilterFormats **ref)
 {
     FORMATS_REF(f, ref);
 }
@@ -327,18 +490,24 @@ void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref)
 }
 
 #define SET_COMMON_FORMATS(ctx, fmts, in_fmts, out_fmts, ref, list) \
-{                                                                   \
     int count = 0, i;                                               \
                                                                     \
+    if (!fmts)                                                      \
+        return AVERROR_BUG;                                         \
+                                                                    \
     for (i = 0; i < ctx->nb_inputs; i++) {                          \
-        if (ctx->inputs[i]) {                                       \
-            ref(fmts, &ctx->inputs[i]->out_fmts);                   \
+        if (ctx->inputs[i] && !ctx->inputs[i]->out_fmts) {          \
+            int ret = ref(fmts, &ctx->inputs[i]->out_fmts);         \
+            if (ret < 0)                                            \
+                return ret;                                         \
             count++;                                                \
         }                                                           \
     }                                                               \
     for (i = 0; i < ctx->nb_outputs; i++) {                         \
-        if (ctx->outputs[i]) {                                      \
-            ref(fmts, &ctx->outputs[i]->in_fmts);                   \
+        if (ctx->outputs[i] && !ctx->outputs[i]->in_fmts) {         \
+            int ret = ref(fmts, &ctx->outputs[i]->in_fmts);         \
+            if (ret < 0)                                            \
+                return ret;                                         \
             count++;                                                \
         }                                                           \
     }                                                               \
@@ -348,17 +517,18 @@ void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref)
         av_freep(&fmts->refs);                                      \
         av_freep(&fmts);                                            \
     }                                                               \
-}
+                                                                    \
+    return 0;
 
-void ff_set_common_channel_layouts(AVFilterContext *ctx,
-                                   AVFilterChannelLayouts *layouts)
+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, channel_layouts);
 }
 
-void ff_set_common_samplerates(AVFilterContext *ctx,
-                               AVFilterFormats *samplerates)
+int ff_set_common_samplerates(AVFilterContext *ctx,
+                              AVFilterFormats *samplerates)
 {
     SET_COMMON_FORMATS(ctx, samplerates, in_samplerates, out_samplerates,
                        ff_formats_ref, formats);
@@ -369,23 +539,170 @@ void ff_set_common_samplerates(AVFilterContext *ctx,
  * formats. If there are no links hooked to this filter, the list of formats is
  * freed.
  */
-void ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
+int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
 {
     SET_COMMON_FORMATS(ctx, formats, in_formats, out_formats,
                        ff_formats_ref, formats);
 }
 
-int ff_default_query_formats(AVFilterContext *ctx)
+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;
 
-    ff_set_common_formats(ctx, ff_all_formats(type));
+    ret = ff_set_common_formats(ctx, ff_all_formats(type));
+    if (ret < 0)
+        return ret;
     if (type == AVMEDIA_TYPE_AUDIO) {
-        ff_set_common_channel_layouts(ctx, ff_all_channel_layouts());
-        ff_set_common_samplerates(ctx, ff_all_samplerates());
+        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_layouts);
+}
+
+int ff_query_formats_all(AVFilterContext *ctx)
+{
+    return default_query_formats_common(ctx, ff_all_channel_counts);
+}
+
+/* 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;
+
+    chlayout = av_get_channel_layout(arg);
+    if (chlayout == 0) {
+        chlayout = strtol(arg, &tail, 10);
+        if (!(*tail == '\0' || *tail == 'c' && *(tail + 1) == '\0') || chlayout <= 0 || chlayout > 63) {
+            av_log(log_ctx, AV_LOG_ERROR, "Invalid channel layout '%s'\n", arg);
+            return AVERROR(EINVAL);
+        }
+        if (nret) {
+            *nret = chlayout;
+            *ret = 0;
+            return 0;
+        }
+    }
+    *ret = chlayout;
+    if (nret)
+        *nret = av_get_channel_layout_nb_channels(chlayout);
+    return 0;
+}
+
+#ifdef TEST
+
+#undef printf
+
+int main(void)
+{
+    const int64_t *cl;
+    char buf[512];
+    int i;
+    const char *teststrings[] ={
+        "blah",
+        "1",
+        "2",
+        "-1",
+        "60",
+        "65",
+        "1c",
+        "2c",
+        "-1c",
+        "60c",
+        "65c",
+        "5.1",
+        "stereo",
+        "1+1+1+1",
+        "1c+1c+1c+1c",
+        "2c+1c",
+        "0x3",
+    };
+
+    for (cl = avfilter_all_channel_layouts; *cl != -1; cl++) {
+        av_get_channel_layout_string(buf, sizeof(buf), -1, *cl);
+        printf("%s\n", buf);
+    }
+
+    for ( i = 0; i<FF_ARRAY_ELEMS(teststrings); i++) {
+        int64_t layout = -1;
+        int count = -1;
+        int ret;
+        ret = ff_parse_channel_layout(&layout, &count, teststrings[i], NULL);
+
+        printf ("%d = ff_parse_channel_layout(%016"PRIX64", %2d, %s);\n", ret ? -1 : 0, layout, count, teststrings[i]);
     }
 
     return 0;
 }
+
+#endif
+