encode_video.c 6.4 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216
  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. * @file
  24. * video encoding with libavcodec API example
  25. *
  26. * @example encode_video.c
  27. */
  28. #include <stdio.h>
  29. #include <stdlib.h>
  30. #include <string.h>
  31. #include <libavcodec/avcodec.h>
  32. #include <libavutil/opt.h>
  33. #include <libavutil/imgutils.h>
  34. static void encode(AVCodecContext *enc_ctx, AVFrame *frame, AVPacket *pkt,
  35. FILE *outfile)
  36. {
  37. int ret;
  38. /* send the frame to the encoder */
  39. if (frame)
  40. printf("Send frame %3"PRId64"\n", frame->pts);
  41. ret = avcodec_send_frame(enc_ctx, frame);
  42. if (ret < 0) {
  43. fprintf(stderr, "Error sending a frame for encoding\n");
  44. exit(1);
  45. }
  46. while (ret >= 0) {
  47. ret = avcodec_receive_packet(enc_ctx, pkt);
  48. if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
  49. return;
  50. else if (ret < 0) {
  51. fprintf(stderr, "Error during encoding\n");
  52. exit(1);
  53. }
  54. printf("Write packet %3"PRId64" (size=%5d)\n", pkt->pts, pkt->size);
  55. fwrite(pkt->data, 1, pkt->size, outfile);
  56. av_packet_unref(pkt);
  57. }
  58. }
  59. int main(int argc, char **argv)
  60. {
  61. const char *filename, *codec_name;
  62. const AVCodec *codec;
  63. AVCodecContext *c= NULL;
  64. int i, ret, x, y;
  65. FILE *f;
  66. AVFrame *frame;
  67. AVPacket *pkt;
  68. uint8_t endcode[] = { 0, 0, 1, 0xb7 };
  69. if (argc <= 2) {
  70. fprintf(stderr, "Usage: %s <output file> <codec name>\n", argv[0]);
  71. exit(0);
  72. }
  73. filename = argv[1];
  74. codec_name = argv[2];
  75. /* find the mpeg1video encoder */
  76. codec = avcodec_find_encoder_by_name(codec_name);
  77. if (!codec) {
  78. fprintf(stderr, "Codec '%s' not found\n", codec_name);
  79. exit(1);
  80. }
  81. c = avcodec_alloc_context3(codec);
  82. if (!c) {
  83. fprintf(stderr, "Could not allocate video codec context\n");
  84. exit(1);
  85. }
  86. pkt = av_packet_alloc();
  87. if (!pkt)
  88. exit(1);
  89. /* put sample parameters */
  90. c->bit_rate = 400000;
  91. /* resolution must be a multiple of two */
  92. c->width = 352;
  93. c->height = 288;
  94. /* frames per second */
  95. c->time_base = (AVRational){1, 25};
  96. c->framerate = (AVRational){25, 1};
  97. /* emit one intra frame every ten frames
  98. * check frame pict_type before passing frame
  99. * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I
  100. * then gop_size is ignored and the output of encoder
  101. * will always be I frame irrespective to gop_size
  102. */
  103. c->gop_size = 10;
  104. c->max_b_frames = 1;
  105. c->pix_fmt = AV_PIX_FMT_YUV420P;
  106. if (codec->id == AV_CODEC_ID_H264)
  107. av_opt_set(c->priv_data, "preset", "slow", 0);
  108. /* open it */
  109. ret = avcodec_open2(c, codec, NULL);
  110. if (ret < 0) {
  111. fprintf(stderr, "Could not open codec: %s\n", av_err2str(ret));
  112. exit(1);
  113. }
  114. f = fopen(filename, "wb");
  115. if (!f) {
  116. fprintf(stderr, "Could not open %s\n", filename);
  117. exit(1);
  118. }
  119. frame = av_frame_alloc();
  120. if (!frame) {
  121. fprintf(stderr, "Could not allocate video frame\n");
  122. exit(1);
  123. }
  124. frame->format = c->pix_fmt;
  125. frame->width = c->width;
  126. frame->height = c->height;
  127. ret = av_frame_get_buffer(frame, 0);
  128. if (ret < 0) {
  129. fprintf(stderr, "Could not allocate the video frame data\n");
  130. exit(1);
  131. }
  132. /* encode 1 second of video */
  133. for (i = 0; i < 25; i++) {
  134. fflush(stdout);
  135. /* Make sure the frame data is writable.
  136. On the first round, the frame is fresh from av_frame_get_buffer()
  137. and therefore we know it is writable.
  138. But on the next rounds, encode() will have called
  139. avcodec_send_frame(), and the codec may have kept a reference to
  140. the frame in its internal structures, that makes the frame
  141. unwritable.
  142. av_frame_make_writable() checks that and allocates a new buffer
  143. for the frame only if necessary.
  144. */
  145. ret = av_frame_make_writable(frame);
  146. if (ret < 0)
  147. exit(1);
  148. /* Prepare a dummy image.
  149. In real code, this is where you would have your own logic for
  150. filling the frame. FFmpeg does not care what you put in the
  151. frame.
  152. */
  153. /* Y */
  154. for (y = 0; y < c->height; y++) {
  155. for (x = 0; x < c->width; x++) {
  156. frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
  157. }
  158. }
  159. /* Cb and Cr */
  160. for (y = 0; y < c->height/2; y++) {
  161. for (x = 0; x < c->width/2; x++) {
  162. frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
  163. frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
  164. }
  165. }
  166. frame->pts = i;
  167. /* encode the image */
  168. encode(c, frame, pkt, f);
  169. }
  170. /* flush the encoder */
  171. encode(c, NULL, pkt, f);
  172. /* Add sequence end code to have a real MPEG file.
  173. It makes only sense because this tiny examples writes packets
  174. directly. This is called "elementary stream" and only works for some
  175. codecs. To create a valid file, you usually need to write packets
  176. into a proper file format or protocol; see muxing.c.
  177. */
  178. if (codec->id == AV_CODEC_ID_MPEG1VIDEO || codec->id == AV_CODEC_ID_MPEG2VIDEO)
  179. fwrite(endcode, 1, sizeof(endcode), f);
  180. fclose(f);
  181. avcodec_free_context(&c);
  182. av_frame_free(&frame);
  183. av_packet_free(&pkt);
  184. return 0;
  185. }