@@ -3,7 +3,7 @@ FFMPEG_LIBS=libavdevice libavformat libavfilter libavcodec libswscale libavutil

 CFLAGS+=$(shell pkg-config  --cflags $(FFMPEG_LIBS))

 LDFLAGS+=$(shell pkg-config --libs $(FFMPEG_LIBS))

-EXAMPLES=encoding metadata muxing

+EXAMPLES=encoding filtering metadata muxing

 OBJS=$(addsuffix .o,$(EXAMPLES))

new file mode 100644

@@ -0,0 +1,230 @@

+/*

+ * Copyright (c) 2010 Nicolas George

+ * Copyright (c) 2011 Stefano Sabatini

+ *

+ * Permission is hereby granted, free of charge, to any person obtaining a copy

+ * of this software and associated documentation files (the "Software"), to deal

+ * in the Software without restriction, including without limitation the rights

+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

+ * copies of the Software, and to permit persons to whom the Software is

+ * furnished to do so, subject to the following conditions:

+ *

+ * The above copyright notice and this permission notice shall be included in

+ * all copies or substantial portions of the Software.

+ *

+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

+ * THE SOFTWARE.

+ */

+

+/**

+ * @file

+ * API example for decoding and filtering

+ */

+

+#define _XOPEN_SOURCE 600 /* for usleep */

+

+#include <libavcodec/avcodec.h>

+#include <libavformat/avformat.h>

+#include <libavfilter/avfiltergraph.h>

+#include <libavfilter/vsink_buffer.h>

+#include <libavfilter/vsrc_buffer.h>

+

+const char *filter_descr = "scale=78:24";

+

+static AVFormatContext *fmt_ctx;

+static AVCodecContext *dec_ctx;

+AVFilterContext *buffersink_ctx;

+AVFilterContext *buffersrc_ctx;

+AVFilterGraph *filter_graph;

+static int video_stream_index = -1;

+static int64_t last_pts = AV_NOPTS_VALUE;

+

+static int open_input_file(const char *filename)

+{

+    int ret, i;

+    AVCodec *dec;

+

+    if ((ret = avformat_open_input(&fmt_ctx, filename, NULL, NULL)) < 0) {

+        av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");

+        return ret;

+    }

+

+    if ((ret = av_find_stream_info(fmt_ctx)) < 0) {

+        av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");

+        return ret;

+    }

+

+    /* select the video stream */

+    ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &dec, 0);

+    if (ret < 0) {

+        av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file\n");

+        return ret;

+    }

+    video_stream_index = ret;

+    dec_ctx = fmt_ctx->streams[video_stream_index]->codec;

+

+    /* init the video decoder */

+    if ((ret = avcodec_open(dec_ctx, dec)) < 0) {

+        av_log(NULL, AV_LOG_ERROR, "Cannot open video decoder\n");

+        return ret;

+    }

+

+    return 0;

+}

+

+static int init_filters(const char *filters_descr)

+{

+    char args[512];

+    int ret;

+    AVFilter *buffersrc  = avfilter_get_by_name("buffer");

+    AVFilter *buffersink = avfilter_get_by_name("buffersink");

+    AVFilterInOut *outputs = avfilter_inout_alloc();

+    AVFilterInOut *inputs  = avfilter_inout_alloc();

+    enum PixelFormat pix_fmts[] = { PIX_FMT_GRAY8, PIX_FMT_NONE };

+    filter_graph = avfilter_graph_alloc();

+

+    /* buffer video source: the decoded frames from the decoder will be inserted here. */

+    snprintf(args, sizeof(args), "%d:%d:%d:%d:%d:%d:%d",

+             dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,

+             dec_ctx->time_base.num, dec_ctx->time_base.den,

+             dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);

+    ret = avfilter_graph_create_filter(&buffersrc_ctx, buffersrc, "in",

+                                       args, NULL, filter_graph);

+    if (ret < 0) {

+        av_log(NULL, AV_LOG_ERROR, "Cannot create buffer source\n");

+        return ret;

+    }

+

+    /* buffer video sink: to terminate the filter chain. */

+    ret = avfilter_graph_create_filter(&buffersink_ctx, buffersink, "out",

+                                       NULL, pix_fmts, filter_graph);

+    if (ret < 0) {

+        av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n");

+        return ret;

+    }

+

+    /* Endpoints for the filter graph. */

+    outputs->name       = av_strdup("in");

+    outputs->filter_ctx = buffersrc_ctx;

+    outputs->pad_idx    = 0;

+    outputs->next       = NULL;

+

+    inputs->name       = av_strdup("out");

+    inputs->filter_ctx = buffersink_ctx;

+    inputs->pad_idx    = 0;

+    inputs->next       = NULL;

+

+    if ((ret = avfilter_graph_parse(filter_graph, filter_descr,

+                                    &inputs, &outputs, NULL)) < 0)

+        return ret;

+

+    if ((ret = avfilter_graph_config(filter_graph, NULL)) < 0)

+        return ret;

+}

+

+static void display_picref(AVFilterBufferRef *picref, AVRational time_base)

+{

+    int x, y;

+    uint8_t *p0, *p;

+    int64_t delay;

+

+    if (picref->pts != AV_NOPTS_VALUE) {

+        if (last_pts != AV_NOPTS_VALUE) {

+            /* sleep roughly the right amount of time;

+             * usleep is in microseconds, just like AV_TIME_BASE. */

+            delay = av_rescale_q(picref->pts - last_pts,

+                                 time_base, AV_TIME_BASE_Q);

+            if (delay > 0 && delay < 1000000)

+                usleep(delay);

+        }

+        last_pts = picref->pts;

+    }

+

+    /* Trivial ASCII grayscale display. */

+    p0 = picref->data[0];

+    puts("\033c");

+    for (y = 0; y < picref->video->h; y++) {

+        p = p0;

+        for (x = 0; x < picref->video->w; x++)

+            putchar(" .-+#"[*(p++) / 52]);

+        putchar('\n');

+        p0 += picref->linesize[0];

+    }

+    fflush(stdout);

+}

+

+int main(int argc, char **argv)

+{

+    int ret;

+    AVPacket packet;

+    AVFrame frame;

+    int got_frame;

+

+    if (argc != 2) {

+        fprintf(stderr, "Usage: %s file\n", argv[0]);

+        exit(1);

+    }

+

+    avcodec_register_all();

+    av_register_all();

+    avfilter_register_all();

+

+    if ((ret = open_input_file(argv[1]) < 0))

+        goto end;

+    if ((ret = init_filters(filter_descr)) < 0)

+        goto end;

+

+    /* read all packets */

+    while (1) {

+        AVFilterBufferRef *picref;

+        if ((ret = av_read_frame(fmt_ctx, &packet)) < 0)

+            break;

+

+        if (packet.stream_index == video_stream_index) {

+            avcodec_get_frame_defaults(&frame);

+            got_frame = 0;

+            ret = avcodec_decode_video2(dec_ctx, &frame, &got_frame, &packet);

+            av_free_packet(&packet);

+            if (ret < 0) {

+                av_log(NULL, AV_LOG_ERROR, "Error decoding video\n");

+                break;

+            }

+

+            if (got_frame) {

+                if (frame.pts == AV_NOPTS_VALUE)

+                    frame.pts = frame.pkt_dts == AV_NOPTS_VALUE ?

+                        frame.pkt_dts : frame.pkt_pts;

+                /* push the decoded frame into the filtergraph */

+                av_vsrc_buffer_add_frame(buffersrc_ctx, &frame);

+

+                /* pull filtered pictures from the filtergraph */

+                while (avfilter_poll_frame(buffersink_ctx->inputs[0])) {

+                    av_vsink_buffer_get_video_buffer_ref(buffersink_ctx, &picref, 0);

+                    if (picref) {

+                        display_picref(picref, buffersink_ctx->inputs[0]->time_base);

+                        avfilter_unref_buffer(picref);

+                    }

+                }

+            }

+        }

+    }

+end:

+    avfilter_graph_free(&filter_graph);

+    if (dec_ctx)

+        avcodec_close(dec_ctx);

+    av_close_input_file(fmt_ctx);

+

+    if (ret < 0 && ret != AVERROR_EOF) {

+        char buf[1024];

+        av_strerror(ret, buf, sizeof(buf));

+        fprintf(stderr, "Error occurred: %s\n", buf);

+        exit(1);

+    }

+

+    exit(0);

+}