avfilter: add loop filters

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

1 files changed, 381 insertions, 0 deletions

diff --git a/libavfilter/f_loop.c b/libavfilter/f_loop.c
new file mode 100644
index 0000000000..d8eb692e77
--- /dev/null
+++ b/libavfilter/f_loop.c
@@ -0,0 +1,381 @@
+/*
+ * Copyright (c) 2016 Paul B Mahol
+ *
+ * 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/audio_fifo.h"
+#include "libavutil/avassert.h"
+#include "libavutil/fifo.h"
+#include "libavutil/internal.h"
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "audio.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct LoopContext {
+    const AVClass *class;
+
+    AVAudioFifo *fifo;
+    AVAudioFifo *left;
+    AVFrame **frames;
+    int nb_frames;
+    int current_frame;
+    int64_t start_pts;
+    int64_t duration;
+    int64_t current_sample;
+    int64_t nb_samples;
+    int64_t ignored_samples;
+
+    int loop;
+    int64_t size;
+    int64_t start;
+    int64_t pts;
+} LoopContext;
+
+#define AFLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+#define VFLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+#define OFFSET(x) offsetof(LoopContext, x)
+
+#if CONFIG_ALOOP_FILTER
+
+static int aconfig_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    LoopContext *s  = ctx->priv;
+
+    s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, 8192);
+    s->left = av_audio_fifo_alloc(inlink->format, inlink->channels, 8192);
+    if (!s->fifo || !s->left)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static av_cold void auninit(AVFilterContext *ctx)
+{
+    LoopContext *s = ctx->priv;
+
+    av_audio_fifo_free(s->fifo);
+    av_audio_fifo_free(s->left);
+}
+
+static int push_samples(AVFilterContext *ctx, int nb_samples)
+{
+    AVFilterLink *outlink = ctx->outputs[0];
+    LoopContext *s = ctx->priv;
+    AVFrame *out;
+    int ret, i = 0;
+
+    while (s->loop != 0 && i < nb_samples) {
+        out = ff_get_audio_buffer(outlink, FFMIN(nb_samples, s->nb_samples - s->current_sample));
+        if (!out)
+            return AVERROR(ENOMEM);
+        ret = av_audio_fifo_peek_at(s->fifo, (void **)out->extended_data, out->nb_samples, s->current_sample);
+        if (ret < 0)
+            return ret;
+        out->pts = s->pts;
+        out->nb_samples = ret;
+        s->pts += out->nb_samples;
+        i += out->nb_samples;
+        s->current_sample += out->nb_samples;
+
+        ret = ff_filter_frame(outlink, out);
+        if (ret < 0)
+            return ret;
+
+        if (s->current_sample >= s->nb_samples) {
+            s->current_sample = 0;
+
+            if (s->loop > 0)
+                s->loop--;
+        }
+    }
+
+    return ret;
+}
+
+static int afilter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    LoopContext *s = ctx->priv;
+    int ret = 0;
+
+    if (s->ignored_samples + frame->nb_samples > s->start && s->size > 0 && s->loop != 0) {
+        if (s->nb_samples < s->size) {
+            int written = FFMIN(frame->nb_samples, s->size - s->nb_samples);
+            int drain = 0;
+
+            ret = av_audio_fifo_write(s->fifo, (void **)frame->extended_data, written);
+            if (ret < 0)
+                return ret;
+            if (!s->nb_samples) {
+                drain = FFMAX(0, s->start - s->ignored_samples);
+                s->pts = frame->pts;
+                av_audio_fifo_drain(s->fifo, drain);
+                s->pts += s->start - s->ignored_samples;
+            }
+            s->nb_samples += ret - drain;
+            drain = frame->nb_samples - written;
+            if (s->nb_samples == s->size && drain > 0) {
+                int ret2;
+
+                ret2 = av_audio_fifo_write(s->left, (void **)frame->extended_data, frame->nb_samples);
+                if (ret2 < 0)
+                   return ret2;
+                av_audio_fifo_drain(s->left, drain);
+            }
+            frame->nb_samples = ret;
+            s->pts += ret;
+            ret = ff_filter_frame(outlink, frame);
+        } else {
+            int nb_samples = frame->nb_samples;
+
+            av_frame_free(&frame);
+            ret = push_samples(ctx, nb_samples);
+        }
+    } else {
+        s->ignored_samples += frame->nb_samples;
+        frame->pts = s->pts;
+        s->pts += frame->nb_samples;
+        ret = ff_filter_frame(outlink, frame);
+    }
+
+    return ret;
+}
+
+static int arequest_frame(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    LoopContext *s = ctx->priv;
+    int ret = 0;
+
+    if ((!s->size) ||
+        (s->nb_samples < s->size) ||
+        (s->nb_samples >= s->size && s->loop == 0)) {
+        int nb_samples = av_audio_fifo_size(s->left);
+
+        if (s->loop == 0 && nb_samples > 0) {
+            AVFrame *out;
+
+            out = ff_get_audio_buffer(outlink, nb_samples);
+            if (!out)
+                return AVERROR(ENOMEM);
+            av_audio_fifo_read(s->left, (void **)out->extended_data, nb_samples);
+            out->pts = s->pts;
+            s->pts += nb_samples;
+            ret = ff_filter_frame(outlink, out);
+            if (ret < 0)
+                return ret;
+        }
+        ret = ff_request_frame(ctx->inputs[0]);
+    } else {
+        ret = push_samples(ctx, 1024);
+    }
+
+    if (ret == AVERROR_EOF && s->nb_samples > 0 && s->loop != 0) {
+        ret = push_samples(ctx, outlink->sample_rate);
+    }
+
+    return ret;
+}
+
+static const AVOption aloop_options[] = {
+    { "loop",  "number of loops",               OFFSET(loop),  AV_OPT_TYPE_INT,   {.i64 = 0 }, -1, INT_MAX,   AFLAGS },
+    { "size",  "max number of samples to loop", OFFSET(size),  AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT32_MAX, AFLAGS },
+    { "start", "set the loop start sample",     OFFSET(start), AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT64_MAX, AFLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(aloop);
+
+static const AVFilterPad ainputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .filter_frame = afilter_frame,
+        .config_props = aconfig_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad aoutputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_AUDIO,
+        .request_frame = arequest_frame,
+    },
+    { NULL }
+};
+
+AVFilter ff_af_aloop = {
+    .name          = "aloop",
+    .description   = NULL_IF_CONFIG_SMALL("Loop audio samples."),
+    .priv_size     = sizeof(LoopContext),
+    .priv_class    = &aloop_class,
+    .uninit        = auninit,
+    .query_formats = ff_query_formats_all,
+    .inputs        = ainputs,
+    .outputs       = aoutputs,
+};
+#endif /* CONFIG_ALOOP_FILTER */
+
+#if CONFIG_LOOP_FILTER
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    LoopContext *s = ctx->priv;
+
+    s->frames = av_calloc(s->size, sizeof(*s->frames));
+    if (!s->frames)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    LoopContext *s = ctx->priv;
+    int i;
+
+    for (i = 0; i < s->nb_frames; i++)
+        av_frame_free(&s->frames[i]);
+
+    av_freep(&s->frames);
+    s->nb_frames = 0;
+}
+
+static int push_frame(AVFilterContext *ctx)
+{
+    AVFilterLink *outlink = ctx->outputs[0];
+    LoopContext *s = ctx->priv;
+    int64_t pts;
+    int ret;
+
+    AVFrame *out = av_frame_clone(s->frames[s->current_frame]);
+
+    if (!out)
+        return AVERROR(ENOMEM);
+    out->pts += s->duration - s->start_pts;
+    pts = out->pts + av_frame_get_pkt_duration(out);
+    ret = ff_filter_frame(outlink, out);
+    s->current_frame++;
+
+    if (s->current_frame >= s->nb_frames) {
+        s->duration = pts;
+        s->current_frame = 0;
+
+        if (s->loop > 0)
+            s->loop--;
+    }
+
+    return ret;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    LoopContext *s = ctx->priv;
+    int ret = 0;
+
+    if (inlink->frame_count >= s->start && s->size > 0 && s->loop != 0) {
+        if (s->nb_frames < s->size) {
+            if (!s->nb_frames)
+                s->start_pts = frame->pts;
+            s->frames[s->nb_frames] = av_frame_clone(frame);
+            if (!s->frames[s->nb_frames]) {
+                av_frame_free(&frame);
+                return AVERROR(ENOMEM);
+            }
+            s->nb_frames++;
+            s->duration = frame->pts + av_frame_get_pkt_duration(frame);
+            ret = ff_filter_frame(outlink, frame);
+        } else {
+            av_frame_free(&frame);
+            ret = push_frame(ctx);
+        }
+    } else {
+        frame->pts += s->duration;
+        ret = ff_filter_frame(outlink, frame);
+    }
+
+    return ret;
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    LoopContext *s = ctx->priv;
+    int ret = 0;
+
+    if ((!s->size) ||
+        (s->nb_frames < s->size) ||
+        (s->nb_frames >= s->size && s->loop == 0)) {
+        ret = ff_request_frame(ctx->inputs[0]);
+    } else {
+        ret = push_frame(ctx);
+    }
+
+    if (ret == AVERROR_EOF && s->nb_frames > 0 && s->loop != 0) {
+        ret = push_frame(ctx);
+    }
+
+    return ret;
+}
+
+static const AVOption loop_options[] = {
+    { "loop",  "number of loops",              OFFSET(loop),  AV_OPT_TYPE_INT,   {.i64 = 0 }, -1, INT_MAX,   VFLAGS },
+    { "size",  "max number of frames to loop", OFFSET(size),  AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT16_MAX, VFLAGS },
+    { "start", "set the loop start frame",     OFFSET(start), AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT64_MAX, VFLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(loop);
+
+static const AVFilterPad inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .request_frame = request_frame,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_loop = {
+    .name        = "loop",
+    .description = NULL_IF_CONFIG_SMALL("Loop video frames."),
+    .priv_size   = sizeof(LoopContext),
+    .priv_class  = &loop_class,
+    .init        = init,
+    .uninit      = uninit,
+    .inputs      = inputs,
+    .outputs     = outputs,
+};
+#endif /* CONFIG_LOOP_FILTER */