1/*
2 * Copyright (c) 2001 Fabrice Bellard
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 * THE SOFTWARE.
21 */
22
23/**
24 * @file
25 * video encoding with libavcodec API example
26 *
27 * @example encode_video.c
28 */
29
30#include <stdio.h>
31#include <stdlib.h>
32#include <string.h>
33
34#include <libavcodec/avcodec.h>
35
36#include <libavutil/opt.h>
37#include <libavutil/imgutils.h>
38
39static void encode(AVCodecContext *enc_ctx, AVFrame *frame, AVPacket *pkt,
40                   FILE *outfile)
41{
42    int ret;
43
44    /* send the frame to the encoder */
45    if (frame)
46        printf("Send frame %3"PRId64"\n", frame->pts);
47
48    ret = avcodec_send_frame(enc_ctx, frame);
49    if (ret < 0) {
50        fprintf(stderr, "Error sending a frame for encoding\n");
51        exit(1);
52    }
53
54    while (ret >= 0) {
55        ret = avcodec_receive_packet(enc_ctx, pkt);
56        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
57            return;
58        else if (ret < 0) {
59            fprintf(stderr, "Error during encoding\n");
60            exit(1);
61        }
62
63        printf("Write packet %3"PRId64" (size=%5d)\n", pkt->pts, pkt->size);
64        fwrite(pkt->data, 1, pkt->size, outfile);
65        av_packet_unref(pkt);
66    }
67}
68
69int main(int argc, char **argv)
70{
71    const char *filename, *codec_name;
72    const AVCodec *codec;
73    AVCodecContext *c= NULL;
74    int i, ret, x, y;
75    FILE *f;
76    AVFrame *frame;
77    AVPacket *pkt;
78    uint8_t endcode[] = { 0, 0, 1, 0xb7 };
79
80    if (argc <= 2) {
81        fprintf(stderr, "Usage: %s <output file> <codec name>\n", argv[0]);
82        exit(0);
83    }
84    filename = argv[1];
85    codec_name = argv[2];
86
87    /* find the mpeg1video encoder */
88    codec = avcodec_find_encoder_by_name(codec_name);
89    if (!codec) {
90        fprintf(stderr, "Codec '%s' not found\n", codec_name);
91        exit(1);
92    }
93
94    c = avcodec_alloc_context3(codec);
95    if (!c) {
96        fprintf(stderr, "Could not allocate video codec context\n");
97        exit(1);
98    }
99
100    pkt = av_packet_alloc();
101    if (!pkt)
102        exit(1);
103
104    /* put sample parameters */
105    c->bit_rate = 400000;
106    /* resolution must be a multiple of two */
107    c->width = 352;
108    c->height = 288;
109    /* frames per second */
110    c->time_base = (AVRational){1, 25};
111    c->framerate = (AVRational){25, 1};
112
113    /* emit one intra frame every ten frames
114     * check frame pict_type before passing frame
115     * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I
116     * then gop_size is ignored and the output of encoder
117     * will always be I frame irrespective to gop_size
118     */
119    c->gop_size = 10;
120    c->max_b_frames = 1;
121    c->pix_fmt = AV_PIX_FMT_YUV420P;
122
123    if (codec->id == AV_CODEC_ID_H264)
124        av_opt_set(c->priv_data, "preset", "slow", 0);
125
126    /* open it */
127    ret = avcodec_open2(c, codec, NULL);
128    if (ret < 0) {
129        fprintf(stderr, "Could not open codec: %s\n", av_err2str(ret));
130        exit(1);
131    }
132
133    f = fopen(filename, "wb");
134    if (!f) {
135        fprintf(stderr, "Could not open %s\n", filename);
136        exit(1);
137    }
138
139    frame = av_frame_alloc();
140    if (!frame) {
141        fprintf(stderr, "Could not allocate video frame\n");
142        exit(1);
143    }
144    frame->format = c->pix_fmt;
145    frame->width  = c->width;
146    frame->height = c->height;
147
148    ret = av_frame_get_buffer(frame, 0);
149    if (ret < 0) {
150        fprintf(stderr, "Could not allocate the video frame data\n");
151        exit(1);
152    }
153
154    /* encode 1 second of video */
155    for (i = 0; i < 25; i++) {
156        fflush(stdout);
157
158        /* Make sure the frame data is writable.
159           On the first round, the frame is fresh from av_frame_get_buffer()
160           and therefore we know it is writable.
161           But on the next rounds, encode() will have called
162           avcodec_send_frame(), and the codec may have kept a reference to
163           the frame in its internal structures, that makes the frame
164           unwritable.
165           av_frame_make_writable() checks that and allocates a new buffer
166           for the frame only if necessary.
167         */
168        ret = av_frame_make_writable(frame);
169        if (ret < 0)
170            exit(1);
171
172        /* Prepare a dummy image.
173           In real code, this is where you would have your own logic for
174           filling the frame. FFmpeg does not care what you put in the
175           frame.
176         */
177        /* Y */
178        for (y = 0; y < c->height; y++) {
179            for (x = 0; x < c->width; x++) {
180                frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
181            }
182        }
183
184        /* Cb and Cr */
185        for (y = 0; y < c->height/2; y++) {
186            for (x = 0; x < c->width/2; x++) {
187                frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
188                frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
189            }
190        }
191
192        frame->pts = i;
193
194        /* encode the image */
195        encode(c, frame, pkt, f);
196    }
197
198    /* flush the encoder */
199    encode(c, NULL, pkt, f);
200
201    /* Add sequence end code to have a real MPEG file.
202       It makes only sense because this tiny examples writes packets
203       directly. This is called "elementary stream" and only works for some
204       codecs. To create a valid file, you usually need to write packets
205       into a proper file format or protocol; see muxing.c.
206     */
207    if (codec->id == AV_CODEC_ID_MPEG1VIDEO || codec->id == AV_CODEC_ID_MPEG2VIDEO)
208        fwrite(endcode, 1, sizeof(endcode), f);
209    fclose(f);
210
211    avcodec_free_context(&c);
212    av_frame_free(&frame);
213    av_packet_free(&pkt);
214
215    return 0;
216}
217