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【飞凌RK3588开发板试用】ffmpeg开发系列之三——编解码

本帖最后由 jf_1137202360 于 2023-3-22 10:03 编辑

前言

  前面我们搭建了ffmpeg的开发环境,进行构建和测试。这一篇实际进行代码编写测试。

准备

  我们可以按照之前的文章从源码构建ffmpeg安装,也可以直接下载编译好的库使用。
引用: wget https://github.com/BtbN/FFmpeg-B ... 4-gpl-shared.tar.xz
sudo apt-get install xz-utils
xz -d ffmpeg-master-latest-linuxARM64-gpl-shared.tar.xz
tar -xvf ffmpeg-master-latest-linuxarm64-gpl-shared.tar

编码测试

代码
引用: vi encode_video.c
代码如下
  1. #include
  2. #include
  3. #include

  5. #include

  7. #include
  8. #include

  10. static void encode(AVCodecContext *enc_ctx, AVFrame *frame, AVPacket *pkt,
  11.                    FILE *outfile)
  12. {
  13.     int ret;

  15.     /* send the frame to the encoder */
  16.     if (frame)
  17.         printf("Send frame %3"PRId64"n", frame->pts);

  19.     ret = avcodec_send_frame(enc_ctx, frame);
  20.     if (ret < 0) {
  21.         fprintf(stderr, "Error sending a frame for encodingn");
  22.         exit(1);
  23.     }

  25.     while (ret >= 0) {
  26.         ret = avcodec_receive_packet(enc_ctx, pkt);
  27.         if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
  28.             return;
  29.         else if (ret < 0) {
  30.             fprintf(stderr, "Error during encodingn");
  31.             exit(1);
  32.         }

  34.         printf("Write packet %3"PRId64" (size=%5d)n", pkt->pts, pkt->size);
  35.         fwrite(pkt->data, 1, pkt->size, outfile);
  36.         av_packet_unref(pkt);
  37.     }
  38. }

  40. int main(int argc, char **argv)
  41. {
  42.     const char *filename, *codec_name;
  43.     const AVCodec *codec;
  44.     AVCodecContext *c= NULL;
  45.     int i, ret, x, y;
  46.     FILE *f;
  47.     AVFrame *frame;
  48.     AVPacket *pkt;
  49.     uint8_t endcode[] = { 0, 0, 1, 0xb7 };

  51.     if (argc <= 2) {
  52.         fprintf(stderr, "Usage: %s n", argv[0]);
  53.         exit(0);
  54.     }
  55.     filename = argv[1];
  56.     codec_name = argv[2];

  58.     /* find the mpeg1video encoder */
  59.     codec = avcodec_find_encoder_by_name(codec_name);
  60.     if (!codec) {
  61.         fprintf(stderr, "Codec '%s' not foundn", codec_name);
  62.         exit(1);
  63.     }

  65.     c = avcodec_alloc_context3(codec);
  66.     if (!c) {
  67.         fprintf(stderr, "Could not allocate video codec contextn");
  68.         exit(1);
  69.     }

  71.     pkt = av_packet_alloc();
  72.     if (!pkt)
  73.         exit(1);

  75.     /* put sample parameters */
  76.     c->bit_rate = 400000;
  77.     /* resolution must be a multiple of two */
  78.     c->width = 352;
  79.     c->height = 288;
  80.     /* frames per second */
  81.     c->time_base = (AVRational){1, 25};
  82.     c->framerate = (AVRational){25, 1};

  84.     /* emit one intra frame every ten frames
  85.      * check frame pict_type before passing frame
  86.      * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I
  87.      * then gop_size is ignored and the output of encoder
  88.      * will always be I frame irrespective to gop_size
  89.      */
  90.     c->gop_size = 10;
  91.     c->max_b_frames = 1;
  92.     c->pix_fmt = AV_PIX_FMT_YUV420P;

  94.     if (codec->id == AV_CODEC_ID_H264)
  95.         av_opt_set(c->priv_data, "preset", "slow", 0);

  97.     /* open it */
  98.     ret = avcodec_open2(c, codec, NULL);
  99.     if (ret < 0) {
  100.         fprintf(stderr, "Could not open codec: %sn", av_err2str(ret));
  101.         exit(1);
  102.     }

  104.     f = fopen(filename, "wb");
  105.     if (!f) {
  106.         fprintf(stderr, "Could not open %sn", filename);
  107.         exit(1);
  108.     }

  110.     frame = av_frame_alloc();
  111.     if (!frame) {
  112.         fprintf(stderr, "Could not allocate video framen");
  113.         exit(1);
  114.     }
  115.     frame->format = c->pix_fmt;
  116.     frame->width  = c->width;
  117.     frame->height = c->height;

  119.     ret = av_frame_get_buffer(frame, 0);
  120.     if (ret < 0) {
  121.         fprintf(stderr, "Could not allocate the video frame datan");
  122.         exit(1);
  123.     }

  125.     /* encode 1 second of video */
  126.     for (i = 0; i < 25; i++) {
  127.         fflush(stdout);

  129.         /* Make sure the frame data is writable.
  130.            On the first round, the frame is fresh from av_frame_get_buffer()
  131.            and therefore we know it is writable.
  132.            But on the next rounds, encode() will have called
  133.            avcodec_send_frame(), and the codec may have kept a reference to
  134.            the frame in its internal structures, that makes the frame
  135.            unwritable.
  136.            av_frame_make_writable() checks that and allocates a new buffer
  137.            for the frame only if necessary.
  138.          */
  139.         ret = av_frame_make_writable(frame);
  140.         if (ret < 0)
  141.             exit(1);

  143.         /* Prepare a dummy image.
  144.            In real code, this is where you would have your own logic for
  145.            filling the frame. FFmpeg does not care what you put in the
  146.            frame.
  147.          */
  148.         /* Y */
  149.         for (y = 0; y < c->height; y++) {
  150.             for (x = 0; x < c->width; x++) {
  151.                 frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
  152.             }
  153.         }

  155.         /* Cb and Cr */
  156.         for (y = 0; y < c->height/2; y++) {
  157.             for (x = 0; x < c->width/2; x++) {
  158.                 frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
  159.                 frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
  160.             }
  161.         }

  163.         frame->pts = i;

  165.         /* encode the image */
  166.         encode(c, frame, pkt, f);
  167.     }

  169.     /* flush the encoder */
  170.     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 mux.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);

  182.     avcodec_free_context(&c);
  183.     av_frame_free(&frame);
  184.     av_packet_free(&pkt);

  186.     return 0;
  187. }

编译

引用: gcc encode_video.c  -Iffmpeg-master-latest-linuxarm64-gpl-shared/include -Lffmpeg-master-latest-linuxarm64-gpl-shared/lib -lavcodec -lavutil -lswresample -o encode

运行

引用: export LD_LIBRARY_PATH=/root/ffmpeg-master-latest-linuxarm64-gpl-shared/lib:$LD_LIBRARY_PATH
./encode encode.bin mpeg1video

结果
  1. root@ok3588:~# export LD_LIBRARY_PATH=/root/ffmpeg-master-latest-linuxarm64-gpl-shared/lib:$LD_LIBRARY_PATH

  3. root@ok3588:~# ./encode encode.bin mpeg1video

  5. Send frame   0

  7. Send frame   1

  9. Write packet   0 (size= 6731)

  11. Send frame   2

  13. Write packet   2 (size= 3727)

  15. Send frame   3

  17. Write packet   1 (size= 1698)

  19. Send frame   4

  21. Write packet   4 (size= 2744)

  23. Send frame   5

  25. Write packet   3 (size= 1676)

  27. Send frame   6

  29. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  31. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  33. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  35. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  37. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  39. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  41. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  43. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  45. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  47. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  49. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  51. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  53. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  55. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  57. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  59. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  61. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  63. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  65. Write packet   6 (size= 2955)

  67. Send frame   7

  69. Write packet   5 (size= 1810)

  71. Send frame   8

  73. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  75. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  77. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  79. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  81. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  83. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  85. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  87. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  89. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  91. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  93. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  95. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  97. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  99. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  101. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  103. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  105. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  107. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  109. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  111. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  113. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  115. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  117. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  119. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  121. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  123. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  125. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  127. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  129. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  131. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  133. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  135. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  137. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  139. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  141. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  143. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  145. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  147. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  149. Write packet   8 (size= 3170)

  151. Send frame   9

  153. Write packet   7 (size= 1937)

  155. Send frame  10

  157. Write packet  10 (size=12306)

  159. Send frame  11

  161. Write packet   9 (size= 2173)

  163. Send frame  12

  165. Write packet  12 (size= 3770)

  167. Send frame  13

  169. Write packet  11 (size= 2064)

  171. Send frame  14

  173. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  175. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  177. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  179. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  181. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  183. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  185. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  187. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  189. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  191. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  193. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  195. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  197. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  199. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  201. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  203. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  205. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  207. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  209. Write packet  14 (size= 3340)

  211. Send frame  15

  213. Write packet  13 (size= 1941)

  215. Send frame  16

  217. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  219. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  221. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  223. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  225. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  227. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  229. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  231. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  233. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  235. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  237. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  239. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  241. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  243. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  245. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  247. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  249. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  251. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  253. Write packet  16 (size= 3121)

  255. Send frame  17

  257. Write packet  15 (size= 1897)

  259. Send frame  18

  261. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  263. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  265. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  267. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  269. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  271. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  273. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  275. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  277. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  279. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  281. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  283. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  285. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  287. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  289. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  291. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  293. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  295. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  297. Write packet  18 (size= 3392)

  299. Send frame  19

  301. Write packet  17 (size= 2172)

  303. Send frame  20

  305. Write packet  20 (size=12266)

  307. Send frame  21

  309. Write packet  19 (size= 2169)

  311. Send frame  22

  313. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  315. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  317. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  319. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  321. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  323. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  325. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  327. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  329. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  331. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  333. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  335. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  337. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  339. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  341. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  343. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  345. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  347. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  349. Write packet  22 (size= 4000)

  351. Send frame  23

  353. Write packet  21 (size= 2018)

  355. Send frame  24

  357. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  359. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  361. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  363. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  365. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  367. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  369. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  371. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  373. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  375. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  377. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  379. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  381. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  383. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  385. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  387. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  389. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  391. [mpeg1video @ 0x55ac6488f0] warning, clipping 1 dct coefficients to -255..255

  393. Write packet  24 (size= 3072)

  395. Write packet  23 (size= 1935)

  397. root@ok3588:~#

解码测试        

代码

引用: vi decode_video.c

代码如下
  1. #include
  2. #include
  3. #include

  5. #include

  7. #define INBUF_SIZE 4096

  9. static void pgm_save(unsigned char* buf, int wrap, int xsize, int ysize,
  10.     char* filename)
  11. {
  12.     FILE* f;
  13.     int i;

  15.     f = fopen(filename, "wb");
  16.     fprintf(f, "P5n%d %dn%dn", xsize, ysize, 255);
  17.     for (i = 0; i < ysize; i++)
  18.         fwrite(buf + i * wrap, 1, xsize, f);
  19.     fclose(f);
  20. }

  22. static void decode(AVCodecContext* dec_ctx, AVFrame* frame, AVPacket* pkt,
  23.     const char* filename)
  24. {
  25.     char buf[1024];
  26.     int ret;

  28.     ret = avcodec_send_packet(dec_ctx, pkt);
  29.     if (ret < 0) {
  30.         fprintf(stderr, "Error sending a packet for decodingn");
  31.         exit(1);
  32.     }

  34.     while (ret >= 0) {
  35.         ret = avcodec_receive_frame(dec_ctx, frame);
  36.         if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
  37.             return;
  38.         else if (ret < 0) {
  39.             fprintf(stderr, "Error during decodingn");
  40.             exit(1);
  41.         }

  43.         printf("saving frame %3"PRId64"n", dec_ctx->frame_num);
  44.         fflush(stdout);

  46.         /* the picture is allocated by the decoder. no need to
  47.            free it */
  48.         snprintf(buf, sizeof(buf), "%s-%"PRId64, filename, dec_ctx->frame_num);
  49.         pgm_save(frame->data[0], frame->linesize[0],
  50.             frame->width, frame->height, buf);
  51.     }
  52. }

  54. int main(int argc, char** argv)
  55. {
  56.     const char* filename, * outfilename;
  57.     const AVCodec* codec;
  58.     AVCodecParserContext* parser;
  59.     AVCodecContext* c = NULL;
  60.     FILE* f;
  61.     AVFrame* frame;
  62.     uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
  63.     uint8_t* data;
  64.     size_t   data_size;
  65.     int ret;
  66.     int eof;
  67.     AVPacket* pkt;

  69.     if (argc <= 2) {
  70.         fprintf(stderr, "Usage: %s n"
  71.             "And check your input file is encoded by mpeg1video please.n", argv[0]);
  72.         exit(0);
  73.     }
  74.     filename = argv[1];
  75.     outfilename = argv[2];

  77.     pkt = av_packet_alloc();
  78.     if (!pkt)
  79.         exit(1);

  81.     /* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */
  82.     memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);

  84.     /* find the MPEG-1 video decoder */
  85.     codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO);
  86.     if (!codec) {
  87.         fprintf(stderr, "Codec not foundn");
  88.         exit(1);
  89.     }

  91.     parser = av_parser_init(codec->id);
  92.     if (!parser) {
  93.         fprintf(stderr, "parser not foundn");
  94.         exit(1);
  95.     }

  97.     c = avcodec_alloc_context3(codec);
  98.     if (!c) {
  99.         fprintf(stderr, "Could not allocate video codec contextn");
  100.         exit(1);
  101.     }

  103.     /* For some codecs, such as msmpeg4 and mpeg4, width and height
  104.        MUST be initialized there because this information is not
  105.        available in the bitstream. */

  107.        /* open it */
  108.     if (avcodec_open2(c, codec, NULL) < 0) {
  109.         fprintf(stderr, "Could not open codecn");
  110.         exit(1);
  111.     }

  113.     f = fopen(filename, "rb");
  114.     if (!f) {
  115.         fprintf(stderr, "Could not open %sn", filename);
  116.         exit(1);
  117.     }

  119.     frame = av_frame_alloc();
  120.     if (!frame) {
  121.         fprintf(stderr, "Could not allocate video framen");
  122.         exit(1);
  123.     }

  125.     do {
  126.         /* read raw data from the input file */
  127.         data_size = fread(inbuf, 1, INBUF_SIZE, f);
  128.         if (ferror(f))
  129.             break;
  130.         eof = !data_size;

  132.         /* use the parser to split the data into frames */
  133.         data = inbuf;
  134.         while (data_size > 0 || eof) {
  135.             ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size,
  136.                 data, data_size, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0);
  137.             if (ret < 0) {
  138.                 fprintf(stderr, "Error while parsingn");
  139.                 exit(1);
  140.             }
  141.             data += ret;
  142.             data_size -= ret;

  144.             if (pkt->size)
  145.                 decode(c, frame, pkt, outfilename);
  146.             else if (eof)
  147.                 break;
  148.         }
  149.     } while (!eof);

  151.     /* flush the decoder */
  152.     decode(c, frame, NULL, outfilename);

  154.     fclose(f);

  156.     av_parser_close(parser);
  157.     avcodec_free_context(&c);
  158.     av_frame_free(&frame);
  159.     av_packet_free(&pkt);

  161.     return 0;
  162. }

编译

引用: gcc decode_video.c  -Iffmpeg-master-latest-linuxarm64-gpl-shared/include -Lffmpeg-master-latest-linuxarm64-gpl-shared/lib -lavcodec -lavutil -lswresample -o decode

运行

引用: export LD_LIBRARY_PATH=/root/ffmpeg-master-latest-linuxarm64-gpl-shared/lib:$LD_LIBRARY_PATH
./decode encode.bin decode.bin

结果
  1. root@ok3588:~# ./decode encode.bin decode.bin

  3. saving frame   1

  5. saving frame   2

  7. saving frame   3

  9. saving frame   4

  11. saving frame   5

  13. saving frame   6

  15. saving frame   7

  17. saving frame   8

  19. saving frame   9

  21. saving frame  10

  23. saving frame  11

  25. saving frame  12

  27. saving frame  13

  29. saving frame  14

  31. saving frame  15

  33. saving frame  16

  35. saving frame  17

  37. saving frame  18

  39. saving frame  19

  41. saving frame  20

  43. saving frame  21

  45. saving frame  22

  47. saving frame  23

  49. saving frame  24

  51. saving frame  25

  53. root@ok3588:~# ls decode* -al

  55. -rwxr-xr-x 1 root root  14736 Mar 21 23:15 decode

  57. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-1

  59. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-10

  61. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-11

  63. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-12

  65. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-13

  67. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-14

  69. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-15

  71. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-16

  73. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-17

  75. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-18

  77. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-19

  79. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-2

  81. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-20

  83. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-21

  85. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-22

  87. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-23

  89. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-24

  91. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-25

  93. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-3

  95. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-4

  97. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-5

  99. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-6

  101. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-7

  103. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-8

  105. -rw-r--r-- 1 root root 101391 Mar 21 23:20 decode.bin-9

  107. -rw-r--r-- 1 root root   6279 Mar 21 23:05 decode_video.c

  109. root@ok3588:~#
播放可以导出编码的文件到PC进行播放

引用: .ffplay.exe -i encode.bin
图片1.png

总结
  由于开发板运行Ubuntu系统性能非常强,能联网进行apt安装包,所以可以直接在开发板上进行开发,免去了交叉编译的麻烦,开发非常方便。通过ffmpeg编解码测试也可以体验到该开发板进行多媒体开发非常简繁方便,且运行高效。

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