lavfi: add trim and atrim filters.

1 files changed, 407 insertions, 0 deletions

diff --git a/libavfilter/trim.c b/libavfilter/trim.c
new file mode 100644
index 0000000000..9a0544d1d1
--- /dev/null
+++ b/libavfilter/trim.c
@@ -0,0 +1,407 @@
+/*
+ * 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
+ */
+
+#include <float.h>
+#include <math.h>
+
+#include "config.h"
+
+#include "libavutil/avassert.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/common.h"
+#include "libavutil/log.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/opt.h"
+#include "libavutil/samplefmt.h"
+
+#include "audio.h"
+#include "avfilter.h"
+#include "internal.h"
+
+typedef struct TrimContext {
+    const AVClass *class;
+
+    /*
+     * AVOptions
+     */
+    double duration;
+    double start_time, end_time;
+    int64_t start_frame, end_frame;
+    /*
+     * in the link timebase for video,
+     * in 1/samplerate for audio
+     */
+    int64_t start_pts, end_pts;
+    int64_t start_sample, end_sample;
+
+    /*
+     * number of video frames that arrived on this filter so far
+     */
+    int64_t nb_frames;
+    /*
+     * number of audio samples that arrived on this filter so far
+     */
+    int64_t nb_samples;
+    /*
+     * timestamp of the first frame in the output, in the timebase units
+     */
+    int64_t first_pts;
+    /*
+     * duration in the timebase units
+     */
+    int64_t duration_tb;
+
+    int64_t next_pts;
+
+    int eof;
+    int got_output;
+} TrimContext;
+
+static int init(AVFilterContext *ctx)
+{
+    TrimContext *s = ctx->priv;
+
+    s->first_pts = AV_NOPTS_VALUE;
+
+    return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    AVFilterContext *ctx = inlink->dst;
+    TrimContext       *s = ctx->priv;
+    AVRational tb = (inlink->type == AVMEDIA_TYPE_VIDEO) ?
+                     inlink->time_base : (AVRational){ 1, inlink->sample_rate };
+
+    if (s->start_time != DBL_MAX) {
+        int64_t start_pts = lrintf(s->start_time / av_q2d(tb));
+        if (s->start_pts == AV_NOPTS_VALUE || start_pts < s->start_pts)
+            s->start_pts = start_pts;
+    }
+    if (s->end_time != DBL_MAX) {
+        int64_t end_pts = lrintf(s->end_time / av_q2d(tb));
+        if (s->end_pts == AV_NOPTS_VALUE || end_pts > s->end_pts)
+            s->end_pts = end_pts;
+    }
+    if (s->duration)
+        s->duration_tb = lrintf(s->duration / av_q2d(tb));
+
+    return 0;
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    TrimContext       *s = ctx->priv;
+    int ret;
+
+    s->got_output = 0;
+    while (!s->got_output) {
+        if (s->eof)
+            return AVERROR_EOF;
+
+        ret = ff_request_frame(ctx->inputs[0]);
+        if (ret < 0)
+            return ret;
+    }
+
+    return 0;
+}
+
+#define OFFSET(x) offsetof(TrimContext, x)
+#define COMMON_OPTS                                                                                                                                                         \
+    { "start",       "Timestamp in seconds of the first frame that "                                                                                                        \
+        "should be passed",                                              OFFSET(start_time),  AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX },       -DBL_MAX, DBL_MAX,     FLAGS }, \
+    { "end",         "Timestamp in seconds of the first frame that "                                                                                                        \
+        "should be dropped again",                                       OFFSET(end_time),    AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX },       -DBL_MAX, DBL_MAX,     FLAGS }, \
+    { "start_pts",   "Timestamp of the first frame that should be "                                                                                                         \
+       " passed",                                                        OFFSET(start_pts),   AV_OPT_TYPE_INT64,  { .i64 = AV_NOPTS_VALUE }, INT64_MIN, INT64_MAX, FLAGS }, \
+    { "end_pts",     "Timestamp of the first frame that should be "                                                                                                         \
+        "dropped again",                                                 OFFSET(end_pts),     AV_OPT_TYPE_INT64,  { .i64 = AV_NOPTS_VALUE }, INT64_MIN, INT64_MAX, FLAGS }, \
+    { "duration",    "Maximum duration of the output in seconds",        OFFSET(duration),    AV_OPT_TYPE_DOUBLE, { .dbl = 0 },                      0,   DBL_MAX, FLAGS },
+
+
+#if CONFIG_TRIM_FILTER
+static int trim_filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *ctx = inlink->dst;
+    TrimContext       *s = ctx->priv;
+    int drop;
+
+    /* drop everything if EOF has already been returned */
+    if (s->eof) {
+        av_frame_free(&frame);
+        return 0;
+    }
+
+    if (s->start_frame >= 0 || s->start_pts != AV_NOPTS_VALUE) {
+        drop = 1;
+        if (s->start_frame >= 0 && s->nb_frames >= s->start_frame)
+            drop = 0;
+        if (s->start_pts != AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE &&
+            frame->pts >= s->start_pts)
+            drop = 0;
+        if (drop)
+            goto drop;
+    }
+
+    if (s->first_pts == AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE)
+        s->first_pts = frame->pts;
+
+    if (s->end_frame != INT64_MAX || s->end_pts != AV_NOPTS_VALUE || s->duration_tb) {
+        drop = 1;
+
+        if (s->end_frame != INT64_MAX && s->nb_frames < s->end_frame)
+            drop = 0;
+        if (s->end_pts != AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE &&
+            frame->pts < s->end_pts)
+            drop = 0;
+        if (s->duration_tb && frame->pts != AV_NOPTS_VALUE &&
+            frame->pts - s->first_pts < s->duration_tb)
+            drop = 0;
+
+        if (drop) {
+            s->eof = 1;
+            goto drop;
+        }
+    }
+
+    s->nb_frames++;
+    s->got_output = 1;
+
+    return ff_filter_frame(ctx->outputs[0], frame);
+
+drop:
+    s->nb_frames++;
+    av_frame_free(&frame);
+    return 0;
+}
+
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM
+static const AVOption trim_options[] = {
+    COMMON_OPTS
+    { "start_frame", "Number of the first frame that should be passed "
+        "to the output",                                                 OFFSET(start_frame), AV_OPT_TYPE_INT64,  { .i64 = -1 },       -1, INT64_MAX, FLAGS },
+    { "end_frame",   "Number of the first frame that should be dropped "
+        "again",                                                         OFFSET(end_frame),   AV_OPT_TYPE_INT64,  { .i64 = INT64_MAX }, 0, INT64_MAX, FLAGS },
+    { NULL },
+};
+#undef FLAGS
+
+static const AVClass trim_class = {
+    .class_name = "trim",
+    .item_name  = av_default_item_name,
+    .option     = trim_options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+static const AVFilterPad trim_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = trim_filter_frame,
+        .config_props = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad trim_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .request_frame = request_frame,
+    },
+    { NULL }
+};
+
+AVFilter avfilter_vf_trim = {
+    .name        = "trim",
+    .description = NULL_IF_CONFIG_SMALL("Pick one continuous section from the input, drop the rest."),
+
+    .init        = init,
+
+    .priv_size   = sizeof(TrimContext),
+    .priv_class  = &trim_class,
+
+    .inputs      = trim_inputs,
+    .outputs     = trim_outputs,
+};
+#endif // CONFIG_TRIM_FILTER
+
+#if CONFIG_ATRIM_FILTER
+static int atrim_filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *ctx = inlink->dst;
+    TrimContext       *s = ctx->priv;
+    int64_t start_sample, end_sample = frame->nb_samples;
+    int64_t pts;
+    int drop;
+
+    /* drop everything if EOF has already been returned */
+    if (s->eof) {
+        av_frame_free(&frame);
+        return 0;
+    }
+
+    if (frame->pts != AV_NOPTS_VALUE)
+        pts = av_rescale_q(frame->pts, inlink->time_base,
+                           (AVRational){ 1, inlink->sample_rate });
+    else
+        pts = s->next_pts;
+    s->next_pts = pts + frame->nb_samples;
+
+    /* check if at least a part of the frame is after the start time */
+    if (s->start_sample < 0 && s->start_pts == AV_NOPTS_VALUE) {
+        start_sample = 0;
+    } else {
+        drop = 1;
+        start_sample = frame->nb_samples;
+
+        if (s->start_sample >= 0 &&
+            s->nb_samples + frame->nb_samples > s->start_sample) {
+            drop         = 0;
+            start_sample = FFMIN(start_sample, s->start_sample - s->nb_samples);
+        }
+
+        if (s->start_pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE &&
+            pts + frame->nb_samples > s->start_pts) {
+            drop = 0;
+            start_sample = FFMIN(start_sample, s->start_pts - pts);
+        }
+
+        if (drop)
+            goto drop;
+    }
+
+    if (s->first_pts == AV_NOPTS_VALUE)
+        s->first_pts = pts + start_sample;
+
+    /* check if at least a part of the frame is before the end time */
+    if (s->end_sample == INT64_MAX && s->end_pts == AV_NOPTS_VALUE && !s->duration_tb) {
+        end_sample = frame->nb_samples;
+    } else {
+        drop       = 1;
+        end_sample = 0;
+
+        if (s->end_sample != INT64_MAX &&
+            s->nb_samples < s->end_sample) {
+            drop       = 0;
+            end_sample = FFMAX(end_sample, s->end_sample - s->nb_samples);
+        }
+
+        if (s->end_pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE &&
+            pts < s->end_pts) {
+            drop       = 0;
+            end_sample = FFMAX(end_sample, s->end_pts - pts);
+        }
+
+        if (s->duration_tb && pts - s->first_pts < s->duration_tb) {
+            drop       = 0;
+            end_sample = FFMAX(end_sample, s->first_pts + s->duration_tb - pts);
+        }
+
+        if (drop) {
+            s->eof = 1;
+            goto drop;
+        }
+    }
+
+    s->nb_samples += frame->nb_samples;
+    start_sample   = FFMAX(0, start_sample);
+    end_sample     = FFMIN(frame->nb_samples, end_sample);
+    av_assert0(start_sample < end_sample);
+
+    if (start_sample) {
+        AVFrame *out = ff_get_audio_buffer(ctx->outputs[0], end_sample - start_sample);
+        if (!out) {
+            av_frame_free(&frame);
+            return AVERROR(ENOMEM);
+        }
+
+        av_frame_copy_props(out, frame);
+        av_samples_copy(out->extended_data, frame->extended_data, 0, start_sample,
+                        out->nb_samples, av_get_channel_layout_nb_channels(frame->channel_layout),
+                        frame->format);
+        if (out->pts != AV_NOPTS_VALUE)
+            out->pts += av_rescale_q(start_sample, (AVRational){ 1, out->sample_rate },
+                                     inlink->time_base);
+
+        av_frame_free(&frame);
+        frame = out;
+    } else
+        frame->nb_samples = end_sample;
+
+    s->got_output = 1;
+    return ff_filter_frame(ctx->outputs[0], frame);
+
+drop:
+    s->nb_samples += frame->nb_samples;
+    av_frame_free(&frame);
+    return 0;
+}
+
+#define FLAGS AV_OPT_FLAG_AUDIO_PARAM
+static const AVOption atrim_options[] = {
+    COMMON_OPTS
+    { "start_sample", "Number of the first audio sample that should be "
+        "passed to the output",                                          OFFSET(start_sample), AV_OPT_TYPE_INT64,  { .i64 = -1 },       -1, INT64_MAX, FLAGS },
+    { "end_sample",   "Number of the first audio sample that should be "
+        "dropped again",                                                 OFFSET(end_sample),   AV_OPT_TYPE_INT64,  { .i64 = INT64_MAX }, 0, INT64_MAX, FLAGS },
+    { NULL },
+};
+#undef FLAGS
+
+static const AVClass atrim_class = {
+    .class_name = "atrim",
+    .item_name  = av_default_item_name,
+    .option     = atrim_options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+static const AVFilterPad atrim_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .filter_frame = atrim_filter_frame,
+        .config_props = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad atrim_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_AUDIO,
+        .request_frame = request_frame,
+    },
+    { NULL }
+};
+
+AVFilter avfilter_af_atrim = {
+    .name        = "atrim",
+    .description = NULL_IF_CONFIG_SMALL("Pick one continuous section from the input, drop the rest."),
+
+    .init        = init,
+
+    .priv_size   = sizeof(TrimContext),
+    .priv_class  = &atrim_class,
+
+    .inputs      = atrim_inputs,
+    .outputs     = atrim_outputs,
+};
+#endif // CONFIG_ATRIM_FILTER