avfilter: add areverse filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Changelog

@@ -18,7 +18,7 @@ version <next>:
 - libkvazaar HEVC encoder
 - erosion, dilation, deflate and inflate video filters
 - Dynamic Audio Normalizer as dynaudnorm filter
-- Reverse filter
+- Reverse video and areverse audio filter
 - Random filter
 - deband filter
 - AAC fixed-point decoding

doc/filters.texi

@@ -8489,7 +8489,7 @@ pixels will slow things down on a large logo.
 This filter uses the repeat_field flag from the Video ES headers and hard repeats
 fields based on its value.
 
-@section reverse
+@section reverse, areverse
 
 Reverse a clip.
 

libavfilter/Makefile

@@ -43,6 +43,7 @@ OBJS-$(CONFIG_APAD_FILTER)                   += af_apad.o
 OBJS-$(CONFIG_APERMS_FILTER)                 += f_perms.o
 OBJS-$(CONFIG_APHASER_FILTER)                += af_aphaser.o generate_wave_table.o
 OBJS-$(CONFIG_ARESAMPLE_FILTER)              += af_aresample.o
+OBJS-$(CONFIG_AREVERSE_FILTER)               += vf_reverse.o
 OBJS-$(CONFIG_ASELECT_FILTER)                += f_select.o
 OBJS-$(CONFIG_ASENDCMD_FILTER)               += f_sendcmd.o
 OBJS-$(CONFIG_ASETNSAMPLES_FILTER)           += af_asetnsamples.o

libavfilter/allfilters.c

@@ -59,6 +59,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(APERMS,         aperms,         af);
     REGISTER_FILTER(APHASER,        aphaser,        af);
     REGISTER_FILTER(ARESAMPLE,      aresample,      af);
+    REGISTER_FILTER(AREVERSE,       areverse,       af);
     REGISTER_FILTER(ASELECT,        aselect,        af);
     REGISTER_FILTER(ASENDCMD,       asendcmd,       af);
     REGISTER_FILTER(ASETNSAMPLES,   asetnsamples,   af);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  5
-#define LIBAVFILTER_VERSION_MINOR  27
+#define LIBAVFILTER_VERSION_MINOR  28
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_reverse.c

@@ -95,6 +95,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
     return 0;
 }
 
+#if CONFIG_REVERSE_FILTER
+
 static int request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
@@ -141,3 +143,117 @@ AVFilter ff_vf_reverse = {
     .inputs      = reverse_inputs,
     .outputs     = reverse_outputs,
 };
+
+#endif /* CONFIG_REVERSE_FILTER */
+
+#if CONFIG_AREVERSE_FILTER
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *formats;
+    AVFilterChannelLayouts *layouts;
+    int ret;
+
+    layouts = ff_all_channel_layouts();
+    if (!layouts)
+        return AVERROR(ENOMEM);
+    ret = ff_set_common_channel_layouts(ctx, layouts);
+    if (ret < 0)
+        return ret;
+
+    ret = ff_set_common_formats(ctx, ff_planar_sample_fmts());
+    if (ret < 0)
+        return ret;
+
+    formats = ff_all_samplerates();
+    if (!formats)
+        return AVERROR(ENOMEM);
+    return ff_set_common_samplerates(ctx, formats);
+}
+
+static int areverse_request_frame(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    ReverseContext *s = ctx->priv;
+    int ret, p, i, j;
+
+    ret = ff_request_frame(ctx->inputs[0]);
+
+    if (ret == AVERROR_EOF && s->nb_frames > 0) {
+        AVFrame *out = s->frames[s->nb_frames - 1];
+        out->pts     = s->pts[s->flush_idx++];
+
+        for (p = 0; p < outlink->channels; p++) {
+            switch (outlink->format) {
+            case AV_SAMPLE_FMT_U8P: {
+                uint8_t *dst = (uint8_t *)out->extended_data[p];
+                for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
+                    FFSWAP(uint8_t, dst[i], dst[j]);
+            }
+                break;
+            case AV_SAMPLE_FMT_S16P: {
+                int16_t *dst = (int16_t *)out->extended_data[p];
+                for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
+                    FFSWAP(int16_t, dst[i], dst[j]);
+            }
+                break;
+            case AV_SAMPLE_FMT_S32P: {
+                int32_t *dst = (int32_t *)out->extended_data[p];
+                for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
+                    FFSWAP(int32_t, dst[i], dst[j]);
+            }
+                break;
+            case AV_SAMPLE_FMT_FLTP: {
+                float *dst = (float *)out->extended_data[p];
+                for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
+                    FFSWAP(float, dst[i], dst[j]);
+            }
+                break;
+            case AV_SAMPLE_FMT_DBLP: {
+                double *dst = (double *)out->extended_data[p];
+                for (i = 0, j = out->nb_samples - 1; i < j; i++, j--)
+                    FFSWAP(double, dst[i], dst[j]);
+            }
+                break;
+            }
+        }
+
+        ret = ff_filter_frame(outlink, out);
+        s->nb_frames--;
+    }
+
+    return ret;
+}
+
+static const AVFilterPad areverse_inputs[] = {
+    {
+        .name           = "default",
+        .type           = AVMEDIA_TYPE_AUDIO,
+        .filter_frame   = filter_frame,
+        .needs_writable = 1,
+    },
+    { NULL }
+};
+
+static const AVFilterPad areverse_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_AUDIO,
+        .request_frame = areverse_request_frame,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_af_areverse = {
+    .name          = "areverse",
+    .description   = NULL_IF_CONFIG_SMALL("Reverse an audio clip."),
+    .query_formats = query_formats,
+    .priv_size     = sizeof(ReverseContext),
+    .init          = init,
+    .uninit        = uninit,
+    .inputs        = areverse_inputs,
+    .outputs       = areverse_outputs,
+};
+
+#endif /* CONFIG_AREVERSE_FILTER */