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• How to encode using the FFMpeg in Android (using H263)

  3 juillet 2012, par Kenny910

  I am trying to follow the sample code on encoding in the ffmpeg document and successfully build a application to encode and generate a mp4 file but I face the following problems :

  1) I am using the H263 for encoding but I can only set the width and height of the AVCodecContext to 176x144, for other case (like 720x480 or 640x480) it will return fail.

  2) I can't play the output mp4 file by using the default Android player, isn't it support H263 mp4 file ? p.s. I can play it by using other player

  3) Is there any sample code on encoding other video frame to make a new video (which mean decode the video and encode it back in different quality setting, also i would like to modify the frame content) ?

  Here is my code, thanks !

  JNIEXPORT jint JNICALL Java_com_ffmpeg_encoder_FFEncoder_nativeEncoder(JNIEnv* env, jobject thiz, jstring filename){
  
  
  
  LOGI("nativeEncoder()");
  
  
  
  avcodec_register_all();
  
  avcodec_init();
  
  av_register_all();
  
  
  
  AVCodec         *codec;
  
  AVCodecContext  *codecCtx;
  
  int             i;
  
  int             out_size;
  
  int             size;
  
  int             x;
  
  int             y;
  
  int             output_buffer_size;
  
  FILE            *file;
  
  AVFrame         *picture;
  
  uint8_t         *output_buffer;
  
  uint8_t         *picture_buffer;
  
  
  
  /* Manual Variables */
  
  int             l;
  
  int             fps = 30;
  
  int             videoLength = 5;
  
  
  
  /* find the H263 video encoder */
  
  codec = avcodec_find_encoder(CODEC_ID_H263);
  
  if (!codec) {
  
      LOGI("avcodec_find_encoder() run fail.");
  
  }
  
  
  
  codecCtx = avcodec_alloc_context();
  
  picture = avcodec_alloc_frame();
  
  
  
  /* put sample parameters */
  
  codecCtx->bit_rate = 400000;
  
  /* resolution must be a multiple of two */
  
  codecCtx->width = 176;
  
  codecCtx->height = 144;
  
  /* frames per second */
  
  codecCtx->time_base = (AVRational){1,fps};
  
  codecCtx->pix_fmt = PIX_FMT_YUV420P;
  
  codecCtx->codec_id = CODEC_ID_H263;
  
  codecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  /* open it */
  
  if (avcodec_open(codecCtx, codec) < 0) {
  
      LOGI("avcodec_open() run fail.");
  
  }
  
  
  
  const char* mfileName = (*env)->GetStringUTFChars(env, filename, 0);
  
  
  
  file = fopen(mfileName, "wb");
  
  if (!file) {
  
      LOGI("fopen() run fail.");
  
  }
  
  
  
  (*env)->ReleaseStringUTFChars(env, filename, mfileName);
  
  
  
  /* alloc image and output buffer */
  
  output_buffer_size = 100000;
  
  output_buffer = malloc(output_buffer_size);
  
  
  
  size = codecCtx->width * codecCtx->height;
  
  picture_buffer = malloc((size * 3) / 2); /* size for YUV 420 */
  
  
  
  picture->data[0] = picture_buffer;
  
  picture->data[1] = picture->data[0] + size;
  
  picture->data[2] = picture->data[1] + size / 4;
  
  picture->linesize[0] = codecCtx->width;
  
  picture->linesize[1] = codecCtx->width / 2;
  
  picture->linesize[2] = codecCtx->width / 2;
  
  
  
  for(l=0;l/encode 1 second of video
  
      for(i=0;i/prepare a dummy image YCbCr
  
          //Y
  
          for(y=0;yheight;y++) {
  
              for(x=0;xwidth;x++) {
  
                  picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
  
              }
  
          }
  
  
  
          //Cb and Cr
  
          for(y=0;yheight/2;y++) {
  
              for(x=0;xwidth/2;x++) {
  
                  picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
  
                  picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
  
              }
  
          }
  
  
  
          //encode the image
  
          out_size = avcodec_encode_video(codecCtx, output_buffer, output_buffer_size, picture);
  
          fwrite(output_buffer, 1, out_size, file);
  
      }
  
  
  
      //get the delayed frames
  
      for(; out_size; i++) {
  
          out_size = avcodec_encode_video(codecCtx, output_buffer, output_buffer_size, NULL);
  
          fwrite(output_buffer, 1, out_size, file);
  
      }
  
  }
  
  
  
  //add sequence end code to have a real mpeg file
  
  output_buffer[0] = 0x00;
  
  output_buffer[1] = 0x00;
  
  output_buffer[2] = 0x01;
  
  output_buffer[3] = 0xb7;
  
  
  
  fwrite(output_buffer, 1, 4, file);
  
  fclose(file);
  
  free(picture_buffer);
  
  free(output_buffer);
  
  avcodec_close(codecCtx);
  
  av_free(codecCtx);
  
  av_free(picture);
  
  
  
  LOGI("finish");
  
  
  
  return 0; }

• Android NDK - FFMpeg, correct video seeking

  15 mars 2012, par sherman

  I want change the seek frame while playing video. I do :

  void Java_ffvideolivewallpaper_frankandrobot_com_NativeCalls_seekFrame(
  JNIEnv *env, jobject this, jint time)

  if (av_seek_frame(pFormatCtx, videoStream, time, AVSEEK_FLAG_ANY) < 0)
  
      __android_log_print(ANDROID_LOG_DEBUG, "ERROR SEEK!!!->>>",
  
              "av_seek_frame failed.");

  Video is displayed incorrectly. How do this correctly ?

• H264 HW Decoding on Android Using FFmpeg-10

  21 septembre 2012, par limitfan

  I've noticed that ffmpeg has already included (libavcodec/libstagefright.cpp) and claimed to support H264's hardware decoding through StageFright framework. I've build the shared library according to (tools/build_libstagefright). But when doing real H264 frame decoding, it seems to be failed at Stagefright_init().
  Does anybody succeed to use this new feature ? Thank you in advance.