2 * Copyright (c) 2010 Nicolas George
3 * Copyright (c) 2011 Stefano Sabatini
5 * Permission is hereby granted, free of charge, to any person obtaining a copy
6 * of this software and associated documentation files (the "Software"), to deal
7 * in the Software without restriction, including without limitation the rights
8 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 * copies of the Software, and to permit persons to whom the Software is
10 * furnished to do so, subject to the following conditions:
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 * API example for decoding and filtering
27 * @example filtering_video.c
30 #define _XOPEN_SOURCE 600 /* for usleep */
33 #include <libavcodec/avcodec.h>
34 #include <libavformat/avformat.h>
35 #include <libavfilter/avfiltergraph.h>
36 #include <libavfilter/avcodec.h>
37 #include <libavfilter/buffersink.h>
38 #include <libavfilter/buffersrc.h>
39 #include <libavutil/opt.h>
41 const char *filter_descr
= "scale=78:24";
43 static AVFormatContext
*fmt_ctx
;
44 static AVCodecContext
*dec_ctx
;
45 AVFilterContext
*buffersink_ctx
;
46 AVFilterContext
*buffersrc_ctx
;
47 AVFilterGraph
*filter_graph
;
48 static int video_stream_index
= -1;
49 static int64_t last_pts
= AV_NOPTS_VALUE
;
51 static int open_input_file(const char *filename
)
56 if ((ret
= avformat_open_input(&fmt_ctx
, filename
, NULL
, NULL
)) < 0) {
57 av_log(NULL
, AV_LOG_ERROR
, "Cannot open input file\n");
61 if ((ret
= avformat_find_stream_info(fmt_ctx
, NULL
)) < 0) {
62 av_log(NULL
, AV_LOG_ERROR
, "Cannot find stream information\n");
66 /* select the video stream */
67 ret
= av_find_best_stream(fmt_ctx
, AVMEDIA_TYPE_VIDEO
, -1, -1, &dec
, 0);
69 av_log(NULL
, AV_LOG_ERROR
, "Cannot find a video stream in the input file\n");
72 video_stream_index
= ret
;
73 dec_ctx
= fmt_ctx
->streams
[video_stream_index
]->codec
;
74 av_opt_set_int(dec_ctx
, "refcounted_frames", 1, 0);
76 /* init the video decoder */
77 if ((ret
= avcodec_open2(dec_ctx
, dec
, NULL
)) < 0) {
78 av_log(NULL
, AV_LOG_ERROR
, "Cannot open video decoder\n");
85 static int init_filters(const char *filters_descr
)
89 AVFilter
*buffersrc
= avfilter_get_by_name("buffer");
90 AVFilter
*buffersink
= avfilter_get_by_name("buffersink");
91 AVFilterInOut
*outputs
= avfilter_inout_alloc();
92 AVFilterInOut
*inputs
= avfilter_inout_alloc();
93 AVRational time_base
= fmt_ctx
->streams
[video_stream_index
]->time_base
;
94 enum AVPixelFormat pix_fmts
[] = { AV_PIX_FMT_GRAY8
, AV_PIX_FMT_NONE
};
96 filter_graph
= avfilter_graph_alloc();
97 if (!outputs
|| !inputs
|| !filter_graph
) {
98 ret
= AVERROR(ENOMEM
);
102 /* buffer video source: the decoded frames from the decoder will be inserted here. */
103 snprintf(args
, sizeof(args
),
104 "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
105 dec_ctx
->width
, dec_ctx
->height
, dec_ctx
->pix_fmt
,
106 time_base
.num
, time_base
.den
,
107 dec_ctx
->sample_aspect_ratio
.num
, dec_ctx
->sample_aspect_ratio
.den
);
109 ret
= avfilter_graph_create_filter(&buffersrc_ctx
, buffersrc
, "in",
110 args
, NULL
, filter_graph
);
112 av_log(NULL
, AV_LOG_ERROR
, "Cannot create buffer source\n");
116 /* buffer video sink: to terminate the filter chain. */
117 ret
= avfilter_graph_create_filter(&buffersink_ctx
, buffersink
, "out",
118 NULL
, NULL
, filter_graph
);
120 av_log(NULL
, AV_LOG_ERROR
, "Cannot create buffer sink\n");
124 ret
= av_opt_set_int_list(buffersink_ctx
, "pix_fmts", pix_fmts
,
125 AV_PIX_FMT_NONE
, AV_OPT_SEARCH_CHILDREN
);
127 av_log(NULL
, AV_LOG_ERROR
, "Cannot set output pixel format\n");
131 /* Endpoints for the filter graph. */
132 outputs
->name
= av_strdup("in");
133 outputs
->filter_ctx
= buffersrc_ctx
;
134 outputs
->pad_idx
= 0;
135 outputs
->next
= NULL
;
137 inputs
->name
= av_strdup("out");
138 inputs
->filter_ctx
= buffersink_ctx
;
142 if ((ret
= avfilter_graph_parse_ptr(filter_graph
, filters_descr
,
143 &inputs
, &outputs
, NULL
)) < 0)
146 if ((ret
= avfilter_graph_config(filter_graph
, NULL
)) < 0)
150 avfilter_inout_free(&inputs
);
151 avfilter_inout_free(&outputs
);
156 static void display_frame(const AVFrame
*frame
, AVRational time_base
)
162 if (frame
->pts
!= AV_NOPTS_VALUE
) {
163 if (last_pts
!= AV_NOPTS_VALUE
) {
164 /* sleep roughly the right amount of time;
165 * usleep is in microseconds, just like AV_TIME_BASE. */
166 delay
= av_rescale_q(frame
->pts
- last_pts
,
167 time_base
, AV_TIME_BASE_Q
);
168 if (delay
> 0 && delay
< 1000000)
171 last_pts
= frame
->pts
;
174 /* Trivial ASCII grayscale display. */
177 for (y
= 0; y
< frame
->height
; y
++) {
179 for (x
= 0; x
< frame
->width
; x
++)
180 putchar(" .-+#"[*(p
++) / 52]);
182 p0
+= frame
->linesize
[0];
187 int main(int argc
, char **argv
)
191 AVFrame
*frame
= av_frame_alloc();
192 AVFrame
*filt_frame
= av_frame_alloc();
195 if (!frame
|| !filt_frame
) {
196 perror("Could not allocate frame");
200 fprintf(stderr
, "Usage: %s file\n", argv
[0]);
205 avfilter_register_all();
207 if ((ret
= open_input_file(argv
[1])) < 0)
209 if ((ret
= init_filters(filter_descr
)) < 0)
212 /* read all packets */
214 if ((ret
= av_read_frame(fmt_ctx
, &packet
)) < 0)
217 if (packet
.stream_index
== video_stream_index
) {
219 ret
= avcodec_decode_video2(dec_ctx
, frame
, &got_frame
, &packet
);
221 av_log(NULL
, AV_LOG_ERROR
, "Error decoding video\n");
226 frame
->pts
= av_frame_get_best_effort_timestamp(frame
);
228 /* push the decoded frame into the filtergraph */
229 if (av_buffersrc_add_frame_flags(buffersrc_ctx
, frame
, AV_BUFFERSRC_FLAG_KEEP_REF
) < 0) {
230 av_log(NULL
, AV_LOG_ERROR
, "Error while feeding the filtergraph\n");
234 /* pull filtered frames from the filtergraph */
236 ret
= av_buffersink_get_frame(buffersink_ctx
, filt_frame
);
237 if (ret
== AVERROR(EAGAIN
) || ret
== AVERROR_EOF
)
241 display_frame(filt_frame
, buffersink_ctx
->inputs
[0]->time_base
);
242 av_frame_unref(filt_frame
);
244 av_frame_unref(frame
);
247 av_free_packet(&packet
);
250 avfilter_graph_free(&filter_graph
);
251 avcodec_close(dec_ctx
);
252 avformat_close_input(&fmt_ctx
);
253 av_frame_free(&frame
);
254 av_frame_free(&filt_frame
);
256 if (ret
< 0 && ret
!= AVERROR_EOF
) {
257 fprintf(stderr
, "Error occurred: %s\n", av_err2str(ret
));