[deb_ffmpeg.git] / ffmpeg / doc / examples / filter_audio.c

/*
 * copyright (c) 2013 Andrew Kelley
 *
 * 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
 */

/**
 * @file
 * libavfilter API usage example.
 *
 * @example filter_audio.c
 * This example will generate a sine wave audio,
 * pass it through a simple filter chain, and then compute the MD5 checksum of
 * the output data.
 *
 * The filter chain it uses is:
 * (input) -> abuffer -> volume -> aformat -> abuffersink -> (output)
 *
 * abuffer: This provides the endpoint where you can feed the decoded samples.
 * volume: In this example we hardcode it to 0.90.
 * aformat: This converts the samples to the samplefreq, channel layout,
 *          and sample format required by the audio device.
 * abuffersink: This provides the endpoint where you can read the samples after
 *              they have passed through the filter chain.
 */

#include <inttypes.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include "libavutil/channel_layout.h"
#include "libavutil/md5.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/samplefmt.h"

#include "libavfilter/avfilter.h"
#include "libavfilter/buffersink.h"
#include "libavfilter/buffersrc.h"

#define INPUT_SAMPLERATE     48000
#define INPUT_FORMAT         AV_SAMPLE_FMT_FLTP
#define INPUT_CHANNEL_LAYOUT AV_CH_LAYOUT_5POINT0

#define VOLUME_VAL 0.90

static int init_filter_graph(AVFilterGraph **graph, AVFilterContext **src,
                             AVFilterContext **sink)
{
    AVFilterGraph *filter_graph;
    AVFilterContext *abuffer_ctx;
    AVFilter        *abuffer;
    AVFilterContext *volume_ctx;
    AVFilter        *volume;
    AVFilterContext *aformat_ctx;
    AVFilter        *aformat;
    AVFilterContext *abuffersink_ctx;
    AVFilter        *abuffersink;

    AVDictionary *options_dict = NULL;
    uint8_t options_str[1024];
    uint8_t ch_layout[64];

    int err;

    /* Create a new filtergraph, which will contain all the filters. */
    filter_graph = avfilter_graph_alloc();
    if (!filter_graph) {
        fprintf(stderr, "Unable to create filter graph.\n");
        return AVERROR(ENOMEM);
    }

    /* Create the abuffer filter;
     * it will be used for feeding the data into the graph. */
    abuffer = avfilter_get_by_name("abuffer");
    if (!abuffer) {
        fprintf(stderr, "Could not find the abuffer filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    abuffer_ctx = avfilter_graph_alloc_filter(filter_graph, abuffer, "src");
    if (!abuffer_ctx) {
        fprintf(stderr, "Could not allocate the abuffer instance.\n");
        return AVERROR(ENOMEM);
    }

    /* Set the filter options through the AVOptions API. */
    av_get_channel_layout_string(ch_layout, sizeof(ch_layout), 0, INPUT_CHANNEL_LAYOUT);
    av_opt_set    (abuffer_ctx, "channel_layout", ch_layout,                            AV_OPT_SEARCH_CHILDREN);
    av_opt_set    (abuffer_ctx, "sample_fmt",     av_get_sample_fmt_name(INPUT_FORMAT), AV_OPT_SEARCH_CHILDREN);
    av_opt_set_q  (abuffer_ctx, "time_base",      (AVRational){ 1, INPUT_SAMPLERATE },  AV_OPT_SEARCH_CHILDREN);
    av_opt_set_int(abuffer_ctx, "sample_rate",    INPUT_SAMPLERATE,                     AV_OPT_SEARCH_CHILDREN);

    /* Now initialize the filter; we pass NULL options, since we have already
     * set all the options above. */
    err = avfilter_init_str(abuffer_ctx, NULL);
    if (err < 0) {
        fprintf(stderr, "Could not initialize the abuffer filter.\n");
        return err;
    }

    /* Create volume filter. */
    volume = avfilter_get_by_name("volume");
    if (!volume) {
        fprintf(stderr, "Could not find the volume filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    volume_ctx = avfilter_graph_alloc_filter(filter_graph, volume, "volume");
    if (!volume_ctx) {
        fprintf(stderr, "Could not allocate the volume instance.\n");
        return AVERROR(ENOMEM);
    }

    /* A different way of passing the options is as key/value pairs in a
     * dictionary. */
    av_dict_set(&options_dict, "volume", AV_STRINGIFY(VOLUME_VAL), 0);
    err = avfilter_init_dict(volume_ctx, &options_dict);
    av_dict_free(&options_dict);
    if (err < 0) {
        fprintf(stderr, "Could not initialize the volume filter.\n");
        return err;
    }

    /* Create the aformat filter;
     * it ensures that the output is of the format we want. */
    aformat = avfilter_get_by_name("aformat");
    if (!aformat) {
        fprintf(stderr, "Could not find the aformat filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    aformat_ctx = avfilter_graph_alloc_filter(filter_graph, aformat, "aformat");
    if (!aformat_ctx) {
        fprintf(stderr, "Could not allocate the aformat instance.\n");
        return AVERROR(ENOMEM);
    }

    /* A third way of passing the options is in a string of the form
     * key1=value1:key2=value2.... */
    snprintf(options_str, sizeof(options_str),
             "sample_fmts=%s:sample_rates=%d:channel_layouts=0x%"PRIx64,
             av_get_sample_fmt_name(AV_SAMPLE_FMT_S16), 44100,
             (uint64_t)AV_CH_LAYOUT_STEREO);
    err = avfilter_init_str(aformat_ctx, options_str);
    if (err < 0) {
        av_log(NULL, AV_LOG_ERROR, "Could not initialize the aformat filter.\n");
        return err;
    }

    /* Finally create the abuffersink filter;
     * it will be used to get the filtered data out of the graph. */
    abuffersink = avfilter_get_by_name("abuffersink");
    if (!abuffersink) {
        fprintf(stderr, "Could not find the abuffersink filter.\n");
        return AVERROR_FILTER_NOT_FOUND;
    }

    abuffersink_ctx = avfilter_graph_alloc_filter(filter_graph, abuffersink, "sink");
    if (!abuffersink_ctx) {
        fprintf(stderr, "Could not allocate the abuffersink instance.\n");
        return AVERROR(ENOMEM);
    }

    /* This filter takes no options. */
    err = avfilter_init_str(abuffersink_ctx, NULL);
    if (err < 0) {
        fprintf(stderr, "Could not initialize the abuffersink instance.\n");
        return err;
    }

    /* Connect the filters;
     * in this simple case the filters just form a linear chain. */
    err = avfilter_link(abuffer_ctx, 0, volume_ctx, 0);
    if (err >= 0)
        err = avfilter_link(volume_ctx, 0, aformat_ctx, 0);
    if (err >= 0)
        err = avfilter_link(aformat_ctx, 0, abuffersink_ctx, 0);
    if (err < 0) {
        fprintf(stderr, "Error connecting filters\n");
        return err;
    }

    /* Configure the graph. */
    err = avfilter_graph_config(filter_graph, NULL);
    if (err < 0) {
        av_log(NULL, AV_LOG_ERROR, "Error configuring the filter graph\n");
        return err;
    }

    *graph = filter_graph;
    *src   = abuffer_ctx;
    *sink  = abuffersink_ctx;

    return 0;
}

/* Do something useful with the filtered data: this simple
 * example just prints the MD5 checksum of each plane to stdout. */
static int process_output(struct AVMD5 *md5, AVFrame *frame)
{
    int planar     = av_sample_fmt_is_planar(frame->format);
    int channels   = av_get_channel_layout_nb_channels(frame->channel_layout);
    int planes     = planar ? channels : 1;
    int bps        = av_get_bytes_per_sample(frame->format);
    int plane_size = bps * frame->nb_samples * (planar ? 1 : channels);
    int i, j;

    for (i = 0; i < planes; i++) {
        uint8_t checksum[16];

        av_md5_init(md5);
        av_md5_sum(checksum, frame->extended_data[i], plane_size);

        fprintf(stdout, "plane %d: 0x", i);
        for (j = 0; j < sizeof(checksum); j++)
            fprintf(stdout, "%02X", checksum[j]);
        fprintf(stdout, "\n");
    }
    fprintf(stdout, "\n");

    return 0;
}

/* Construct a frame of audio data to be filtered;
 * this simple example just synthesizes a sine wave. */
static int get_input(AVFrame *frame, int frame_num)
{
    int err, i, j;

#define FRAME_SIZE 1024

    /* Set up the frame properties and allocate the buffer for the data. */
    frame->sample_rate    = INPUT_SAMPLERATE;
    frame->format         = INPUT_FORMAT;
    frame->channel_layout = INPUT_CHANNEL_LAYOUT;
    frame->nb_samples     = FRAME_SIZE;
    frame->pts            = frame_num * FRAME_SIZE;

    err = av_frame_get_buffer(frame, 0);
    if (err < 0)
        return err;

    /* Fill the data for each channel. */
    for (i = 0; i < 5; i++) {
        float *data = (float*)frame->extended_data[i];

        for (j = 0; j < frame->nb_samples; j++)
            data[j] = sin(2 * M_PI * (frame_num + j) * (i + 1) / FRAME_SIZE);
    }

    return 0;
}

int main(int argc, char *argv[])
{
    struct AVMD5 *md5;
    AVFilterGraph *graph;
    AVFilterContext *src, *sink;
    AVFrame *frame;
    uint8_t errstr[1024];
    float duration;
    int err, nb_frames, i;

    if (argc < 2) {
        fprintf(stderr, "Usage: %s <duration>\n", argv[0]);
        return 1;
    }

    duration  = atof(argv[1]);
    nb_frames = duration * INPUT_SAMPLERATE / FRAME_SIZE;
    if (nb_frames <= 0) {
        fprintf(stderr, "Invalid duration: %s\n", argv[1]);
        return 1;
    }

    avfilter_register_all();

    /* Allocate the frame we will be using to store the data. */
    frame  = av_frame_alloc();
    if (!frame) {
        fprintf(stderr, "Error allocating the frame\n");
        return 1;
    }

    md5 = av_md5_alloc();
    if (!md5) {
        fprintf(stderr, "Error allocating the MD5 context\n");
        return 1;
    }

    /* Set up the filtergraph. */
    err = init_filter_graph(&graph, &src, &sink);
    if (err < 0) {
        fprintf(stderr, "Unable to init filter graph:");
        goto fail;
    }

    /* the main filtering loop */
    for (i = 0; i < nb_frames; i++) {
        /* get an input frame to be filtered */
        err = get_input(frame, i);
        if (err < 0) {
            fprintf(stderr, "Error generating input frame:");
            goto fail;
        }

        /* Send the frame to the input of the filtergraph. */
        err = av_buffersrc_add_frame(src, frame);
        if (err < 0) {
            av_frame_unref(frame);
            fprintf(stderr, "Error submitting the frame to the filtergraph:");
            goto fail;
        }

        /* Get all the filtered output that is available. */
        while ((err = av_buffersink_get_frame(sink, frame)) >= 0) {
            /* now do something with our filtered frame */
            err = process_output(md5, frame);
            if (err < 0) {
                fprintf(stderr, "Error processing the filtered frame:");
                goto fail;
            }
            av_frame_unref(frame);
        }

        if (err == AVERROR(EAGAIN)) {
            /* Need to feed more frames in. */
            continue;
        } else if (err == AVERROR_EOF) {
            /* Nothing more to do, finish. */
            break;
        } else if (err < 0) {
            /* An error occurred. */
            fprintf(stderr, "Error filtering the data:");
            goto fail;
        }
    }

    avfilter_graph_free(&graph);
    av_frame_free(&frame);
    av_freep(&md5);

    return 0;

fail:
    av_strerror(err, errstr, sizeof(errstr));
    fprintf(stderr, "%s\n", errstr);
    return 1;
}
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* copyright (c) 2013 Andrew Kelley
	3	*
	4	* This file is part of FFmpeg.
	5	*
	6	* FFmpeg is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; either
	9	* version 2.1 of the License, or (at your option) any later version.
	10	*
	11	* FFmpeg is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with FFmpeg; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20
	21	/**
	22	* @file
	23	* libavfilter API usage example.
	24	*
	25	* @example filter_audio.c
	26	* This example will generate a sine wave audio,
	27	* pass it through a simple filter chain, and then compute the MD5 checksum of
	28	* the output data.
	29	*
	30	* The filter chain it uses is:
	31	* (input) -> abuffer -> volume -> aformat -> abuffersink -> (output)
	32	*
	33	* abuffer: This provides the endpoint where you can feed the decoded samples.
	34	* volume: In this example we hardcode it to 0.90.
	35	* aformat: This converts the samples to the samplefreq, channel layout,
	36	* and sample format required by the audio device.
	37	* abuffersink: This provides the endpoint where you can read the samples after
	38	* they have passed through the filter chain.
	39	*/
	40
	41	#include <inttypes.h>
	42	#include <math.h>
	43	#include <stdio.h>
	44	#include <stdlib.h>
	45
	46	#include "libavutil/channel_layout.h"
	47	#include "libavutil/md5.h"
	48	#include "libavutil/mem.h"
	49	#include "libavutil/opt.h"
	50	#include "libavutil/samplefmt.h"
	51
	52	#include "libavfilter/avfilter.h"
	53	#include "libavfilter/buffersink.h"
	54	#include "libavfilter/buffersrc.h"
	55
	56	#define INPUT_SAMPLERATE 48000
	57	#define INPUT_FORMAT AV_SAMPLE_FMT_FLTP
	58	#define INPUT_CHANNEL_LAYOUT AV_CH_LAYOUT_5POINT0
	59
	60	#define VOLUME_VAL 0.90
	61
	62	static int init_filter_graph(AVFilterGraph graph, AVFilterContext src,
	63	AVFilterContext **sink)
	64	{
65	AVFilterGraph *filter_graph;
66	AVFilterContext *abuffer_ctx;
67	AVFilter *abuffer;
68	AVFilterContext *volume_ctx;
69	AVFilter *volume;
70	AVFilterContext *aformat_ctx;
71	AVFilter *aformat;
72	AVFilterContext *abuffersink_ctx;
73	AVFilter *abuffersink;
74
75	AVDictionary *options_dict = NULL;
76	uint8_t options_str[1024];
77	uint8_t ch_layout[64];
78
79	int err;
80
81	/* Create a new filtergraph, which will contain all the filters. */
82	filter_graph = avfilter_graph_alloc();
83	if (!filter_graph) {
84	fprintf(stderr, "Unable to create filter graph.\n");
85	return AVERROR(ENOMEM);
86	}
87
88	/* Create the abuffer filter;
89	* it will be used for feeding the data into the graph. */
90	abuffer = avfilter_get_by_name("abuffer");
91	if (!abuffer) {
92	fprintf(stderr, "Could not find the abuffer filter.\n");
93	return AVERROR_FILTER_NOT_FOUND;
94	}
95
96	abuffer_ctx = avfilter_graph_alloc_filter(filter_graph, abuffer, "src");
97	if (!abuffer_ctx) {
98	fprintf(stderr, "Could not allocate the abuffer instance.\n");
99	return AVERROR(ENOMEM);
100	}
101
102	/* Set the filter options through the AVOptions API. */
103	av_get_channel_layout_string(ch_layout, sizeof(ch_layout), 0, INPUT_CHANNEL_LAYOUT);
104	av_opt_set (abuffer_ctx, "channel_layout", ch_layout, AV_OPT_SEARCH_CHILDREN);
105	av_opt_set (abuffer_ctx, "sample_fmt", av_get_sample_fmt_name(INPUT_FORMAT), AV_OPT_SEARCH_CHILDREN);
106	av_opt_set_q (abuffer_ctx, "time_base", (AVRational){ 1, INPUT_SAMPLERATE }, AV_OPT_SEARCH_CHILDREN);
107	av_opt_set_int(abuffer_ctx, "sample_rate", INPUT_SAMPLERATE, AV_OPT_SEARCH_CHILDREN);
108
109	/* Now initialize the filter; we pass NULL options, since we have already
110	* set all the options above. */
111	err = avfilter_init_str(abuffer_ctx, NULL);
112	if (err < 0) {
113	fprintf(stderr, "Could not initialize the abuffer filter.\n");
114	return err;
115	}
116
117	/* Create volume filter. */
118	volume = avfilter_get_by_name("volume");
119	if (!volume) {
120	fprintf(stderr, "Could not find the volume filter.\n");
121	return AVERROR_FILTER_NOT_FOUND;
122	}
123
124	volume_ctx = avfilter_graph_alloc_filter(filter_graph, volume, "volume");
125	if (!volume_ctx) {
126	fprintf(stderr, "Could not allocate the volume instance.\n");
127	return AVERROR(ENOMEM);
128	}
129
130	/* A different way of passing the options is as key/value pairs in a
131	* dictionary. */
132	av_dict_set(&options_dict, "volume", AV_STRINGIFY(VOLUME_VAL), 0);
133	err = avfilter_init_dict(volume_ctx, &options_dict);
134	av_dict_free(&options_dict);
135	if (err < 0) {
136	fprintf(stderr, "Could not initialize the volume filter.\n");
137	return err;
138	}
139
140	/* Create the aformat filter;
141	* it ensures that the output is of the format we want. */
142	aformat = avfilter_get_by_name("aformat");
143	if (!aformat) {
144	fprintf(stderr, "Could not find the aformat filter.\n");
145	return AVERROR_FILTER_NOT_FOUND;
146	}
147
148	aformat_ctx = avfilter_graph_alloc_filter(filter_graph, aformat, "aformat");
149	if (!aformat_ctx) {
150	fprintf(stderr, "Could not allocate the aformat instance.\n");
151	return AVERROR(ENOMEM);
152	}
153
154	/* A third way of passing the options is in a string of the form
155	* key1=value1:key2=value2.... */
156	snprintf(options_str, sizeof(options_str),
157	"sample_fmts=%s:sample_rates=%d:channel_layouts=0x%"PRIx64,
158	av_get_sample_fmt_name(AV_SAMPLE_FMT_S16), 44100,
159	(uint64_t)AV_CH_LAYOUT_STEREO);
160	err = avfilter_init_str(aformat_ctx, options_str);
161	if (err < 0) {
162	av_log(NULL, AV_LOG_ERROR, "Could not initialize the aformat filter.\n");
163	return err;
164	}
165
166	/* Finally create the abuffersink filter;
167	* it will be used to get the filtered data out of the graph. */
168	abuffersink = avfilter_get_by_name("abuffersink");
169	if (!abuffersink) {
170	fprintf(stderr, "Could not find the abuffersink filter.\n");
171	return AVERROR_FILTER_NOT_FOUND;
172	}
173
174	abuffersink_ctx = avfilter_graph_alloc_filter(filter_graph, abuffersink, "sink");
175	if (!abuffersink_ctx) {
176	fprintf(stderr, "Could not allocate the abuffersink instance.\n");
177	return AVERROR(ENOMEM);
178	}
179
180	/* This filter takes no options. */
181	err = avfilter_init_str(abuffersink_ctx, NULL);
182	if (err < 0) {
183	fprintf(stderr, "Could not initialize the abuffersink instance.\n");
184	return err;
185	}
186
187	/* Connect the filters;
188	* in this simple case the filters just form a linear chain. */
189	err = avfilter_link(abuffer_ctx, 0, volume_ctx, 0);
190	if (err >= 0)
191	err = avfilter_link(volume_ctx, 0, aformat_ctx, 0);
192	if (err >= 0)
193	err = avfilter_link(aformat_ctx, 0, abuffersink_ctx, 0);
194	if (err < 0) {
195	fprintf(stderr, "Error connecting filters\n");
196	return err;
197	}
198
199	/* Configure the graph. */
200	err = avfilter_graph_config(filter_graph, NULL);
201	if (err < 0) {
202	av_log(NULL, AV_LOG_ERROR, "Error configuring the filter graph\n");
203	return err;
204	}
205
206	*graph = filter_graph;
207	*src = abuffer_ctx;
208	*sink = abuffersink_ctx;
209
210	return 0;
211	}
212
213	/* Do something useful with the filtered data: this simple
214	* example just prints the MD5 checksum of each plane to stdout. */
215	static int process_output(struct AVMD5 md5, AVFrame frame)
216	{
217	int planar = av_sample_fmt_is_planar(frame->format);
218	int channels = av_get_channel_layout_nb_channels(frame->channel_layout);
219	int planes = planar ? channels : 1;
220	int bps = av_get_bytes_per_sample(frame->format);
221	int plane_size = bps * frame->nb_samples * (planar ? 1 : channels);
222	int i, j;
223
224	for (i = 0; i < planes; i++) {
225	uint8_t checksum[16];
226
227	av_md5_init(md5);
228	av_md5_sum(checksum, frame->extended_data[i], plane_size);
229
230	fprintf(stdout, "plane %d: 0x", i);
231	for (j = 0; j < sizeof(checksum); j++)
232	fprintf(stdout, "%02X", checksum[j]);
233	fprintf(stdout, "\n");
234	}
235	fprintf(stdout, "\n");
236
237	return 0;
238	}
239
240	/* Construct a frame of audio data to be filtered;
241	* this simple example just synthesizes a sine wave. */
242	static int get_input(AVFrame *frame, int frame_num)
243	{
244	int err, i, j;
245
246	#define FRAME_SIZE 1024
247
248	/* Set up the frame properties and allocate the buffer for the data. */
249	frame->sample_rate = INPUT_SAMPLERATE;
250	frame->format = INPUT_FORMAT;
251	frame->channel_layout = INPUT_CHANNEL_LAYOUT;
252	frame->nb_samples = FRAME_SIZE;
253	frame->pts = frame_num * FRAME_SIZE;
254
255	err = av_frame_get_buffer(frame, 0);
256	if (err < 0)
257	return err;
258
259	/* Fill the data for each channel. */
260	for (i = 0; i < 5; i++) {
261	float data = (float)frame->extended_data[i];
262
263	for (j = 0; j < frame->nb_samples; j++)
264	data[j] = sin(2 * M_PI * (frame_num + j) * (i + 1) / FRAME_SIZE);
265	}
266
267	return 0;
268	}
269
270	int main(int argc, char *argv[])
271	{
272	struct AVMD5 *md5;
273	AVFilterGraph *graph;
274	AVFilterContext src, sink;
275	AVFrame *frame;
276	uint8_t errstr[1024];
277	float duration;
278	int err, nb_frames, i;
279
280	if (argc < 2) {
281	fprintf(stderr, "Usage: %s <duration>\n", argv[0]);
282	return 1;
283	}
284
285	duration = atof(argv[1]);
286	nb_frames = duration * INPUT_SAMPLERATE / FRAME_SIZE;
287	if (nb_frames <= 0) {
288	fprintf(stderr, "Invalid duration: %s\n", argv[1]);
289	return 1;
290	}
291
292	avfilter_register_all();
293
294	/* Allocate the frame we will be using to store the data. */
295	frame = av_frame_alloc();
296	if (!frame) {
297	fprintf(stderr, "Error allocating the frame\n");
298	return 1;
299	}
300
301	md5 = av_md5_alloc();
302	if (!md5) {
303	fprintf(stderr, "Error allocating the MD5 context\n");
304	return 1;
305	}
306
307	/* Set up the filtergraph. */
308	err = init_filter_graph(&graph, &src, &sink);
309	if (err < 0) {
310	fprintf(stderr, "Unable to init filter graph:");
311	goto fail;
312	}
313
314	/* the main filtering loop */
315	for (i = 0; i < nb_frames; i++) {
316	/* get an input frame to be filtered */
317	err = get_input(frame, i);
318	if (err < 0) {
319	fprintf(stderr, "Error generating input frame:");
320	goto fail;
321	}
322
323	/* Send the frame to the input of the filtergraph. */
324	err = av_buffersrc_add_frame(src, frame);
325	if (err < 0) {
326	av_frame_unref(frame);
327	fprintf(stderr, "Error submitting the frame to the filtergraph:");
328	goto fail;
329	}
330
331	/* Get all the filtered output that is available. */
332	while ((err = av_buffersink_get_frame(sink, frame)) >= 0) {
333	/* now do something with our filtered frame */
334	err = process_output(md5, frame);
335	if (err < 0) {
336	fprintf(stderr, "Error processing the filtered frame:");
337	goto fail;
338	}
339	av_frame_unref(frame);
340	}
341
342	if (err == AVERROR(EAGAIN)) {
343	/* Need to feed more frames in. */
344	continue;
345	} else if (err == AVERROR_EOF) {
346	/* Nothing more to do, finish. */
347	break;
348	} else if (err < 0) {
349	/* An error occurred. */
350	fprintf(stderr, "Error filtering the data:");
351	goto fail;
352	}
353	}
354
355	avfilter_graph_free(&graph);
356	av_frame_free(&frame);
357	av_freep(&md5);
358
359	return 0;
360
361	fail:
362	av_strerror(err, errstr, sizeof(errstr));
363	fprintf(stderr, "%s\n", errstr);
364	return 1;
365	}