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• ffmpeg : concat videos and images

  23 mai 2016, par Yosko

  I have 2 videos (same resolution, same encoding) files that I want to concat and I want to insert some text for 3 seconds between them, as a splitter. I’m doing this with ffmpeg on Windows.

  Optional ideas that I would be interested in :

  • avoid reencoding the video in the process
  • having a fade in / fade out at the intersection of each part

  For now, I made the text as an image (but I am open to other suggestions). Let’s say I have :

  • video1.mp4 : 6:33
  • splitter.png (same resolution as video1.mp4)
  • video2.mp4 : 16:44

  I have tried a few things, but I always end up with the same problem : the video is 23:20 (video1 + 3 seconds + video2), but the 3 seconds gap is just the last video1 frame frozen instead of my image/text...

  Any Idea what I did wrong or how I should achieve this ?

  Here is what I tried so far :

  Method 1 : image to video

  Turn the image into a 3 seconds mp4 film, then concat (demuxer) it with the others :

  ffmpeg -loop 1 -f image2 -i splitter.png -r 30 -t 3 splitter.mp4
  
  ffmpeg -f concat -i input.txt -codec copy output.mp4

  Where the input.txt looks like :

  file 'E:\video1.mp4'
  
  file 'E:\splitter.mp4'
  
  file 'E:\video2.mp4'

  The content of splitter.png is visible in the splitter.mp4, but not in the output.mp4. Also I’m not entirely sure the splitter.mp4 respects the exact same encoding as the 2 videos, and I don’t know how to verify that.

  Method 2 : insert image frames

  Directly run the concat (demuxer) 90 times (30fps -> 3 seconds) on the image

  ffmpeg -f concat -i input.txt -codec copy output.mp4

  Where the input.txt looks like :

  file 'E:\video1.mp4'
  
  file 'E:\splitter.png'
  
  ...
  
  file 'E:\splitter.png'
  
  file 'E:\video2.mp4'

  Edit : possible solution ?

  Since all I’m doing is screencasting, I might as well screencast my splitter image. This way I would be sure of the audio & video encoding and wouldn’t have any problem merging and it wouldn’t need any reencoding... I know it might sound dumb, but it would probably do the trick...

  Note : I didn’t have try it, since I already worked through Openshot.

• Java.lang.UnsatisfiedLinkError : No implementation found for int [duplicate]

  28 mars 2017, par Muthukumar Subramaniam

  This question already has an answer here :

  • Android NDK C++ JNI (no implementation found for native…)
    
    6 answers
    

  I executed youtube watch me android application project. I just add some classes in my project and build with ndk. I got the error like

  java.lang.UnsatisfiedLinkError : No implementation found for int com.ephronsystem.mobilizerapp.Ffmpeg.encodeVideoFrame(byte[]) (tried Java_com_ephronsystem_mobilizerapp_Ffmpeg_encodeVideoFrame and Java_com_ephronsystem_mobilizerapp_Ffmpeg_encodeVideoFrame___3B).

  My code :

  package com.ephronsystem.mobilizerapp;
  
  
  
  public class Ffmpeg {
  
  
  
       static {
  
          System.loadLibrary("ffmpeg");
  
      }
  
  
  
      public static native boolean init(int width, int height, int audio_sample_rate, String rtmpUrl);
  
  
  
      public static native void shutdown();
  
  
  
      // Returns the size of the encoded frame.
  
      public static native int encodeVideoFrame(byte[] yuv_image);
  
  
  
      public static native int encodeAudioFrame(short[] audio_data, int length);
  
  }

  This is ffmpeg-jni.c

   #include <android></android>log.h>
  
  #include 
  
  #include 
  
  #include "libavcodec/avcodec.h"
  
  #include "libavformat/avformat.h"
  
  #include "libavutil/opt.h"
  
  
  
  #ifdef __cplusplus
  
  extern "C" {
  
  #endif
  
  
  
  JNIEXPORT jboolean JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_init(JNIEnv *env, jobject thiz,
  
                                                                   jint width, jint height,
  
                                                                   jint audio_sample_rate,
  
                                                                   jstring rtmp_url);
  
  JNIEXPORT void JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_shutdown(JNIEnv *env,
  
  jobject thiz
  
  );
  
  JNIEXPORT jint JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_encodeVideoFrame(JNIEnv
  
  *env,
  
  jobject thiz,
  
          jbyteArray
  
  yuv_image);
  
  JNIEXPORT jint JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_encodeAudioFrame(JNIEnv *env,
  
                                                                               jobject thiz,
  
                                                                               jshortArray audio_data,
  
                                                                               jint length);
  
  
  
  #ifdef __cplusplus
  
  }
  
  #endif
  
  
  
  #define LOGI(...) __android_log_print(ANDROID_LOG_INFO, "ffmpeg-jni", __VA_ARGS__)
  
  #define URL_WRONLY 2
  
          static AVFormatContext *fmt_context;
  
          static AVStream *video_stream;
  
          static AVStream *audio_stream;
  
  
  
          static int pts
  
  = 0;
  
  static int last_audio_pts = 0;
  
  
  
  // Buffers for UV format conversion
  
  static unsigned char *u_buf;
  
  static unsigned char *v_buf;
  
  
  
  static int enable_audio = 1;
  
  static int64_t audio_samples_written = 0;
  
  static int audio_sample_rate = 0;
  
  
  
  // Stupid buffer for audio samples. Not even a proper ring buffer
  
  #define AUDIO_MAX_BUF_SIZE 16384  // 2x what we get from Java
  
  static short audio_buf[AUDIO_MAX_BUF_SIZE];
  
  static int audio_buf_size = 0;
  
  
  
  void AudioBuffer_Push(const short *audio, int num_samples) {
  
      if (audio_buf_size >= AUDIO_MAX_BUF_SIZE - num_samples) {
  
          LOGI("AUDIO BUFFER OVERFLOW: %i + %i > %i", audio_buf_size, num_samples,
  
               AUDIO_MAX_BUF_SIZE);
  
          return;
  
      }
  
      for (int i = 0; i &lt; num_samples; i++) {
  
          audio_buf[audio_buf_size++] = audio[i];
  
      }
  
  }
  
  
  
  int AudioBuffer_Size() { return audio_buf_size; }
  
  
  
  short *AudioBuffer_Get() { return audio_buf; }
  
  
  
  void AudioBuffer_Pop(int num_samples) {
  
      if (num_samples > audio_buf_size) {
  
          LOGI("Audio buffer Pop WTF: %i vs %i", num_samples, audio_buf_size);
  
          return;
  
      }
  
      memmove(audio_buf, audio_buf + num_samples, num_samples * sizeof(short));
  
      audio_buf_size -= num_samples;
  
  }
  
  
  
  void AudioBuffer_Clear() {
  
      memset(audio_buf, 0, sizeof(audio_buf));
  
      audio_buf_size = 0;
  
  }
  
  
  
  static void log_callback(void *ptr, int level, const char *fmt, va_list vl) {
  
      char x[2048];
  
      vsnprintf(x, 2048, fmt, vl);
  
      LOGI(x);
  
  }
  
  
  
  JNIEXPORT jboolean JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_init(JNIEnv *env, jobject thiz,
  
                                                                   jint width, jint height,
  
                                                                   jint audio_sample_rate_param,
  
                                                                   jstring rtmp_url) {
  
      avcodec_register_all();
  
      av_register_all();
  
      av_log_set_callback(log_callback);
  
  
  
      fmt_context = avformat_alloc_context();
  
      AVOutputFormat *ofmt = av_guess_format("flv", NULL, NULL);
  
      if (ofmt) {
  
          LOGI("av_guess_format returned %s", ofmt->long_name);
  
      } else {
  
          LOGI("av_guess_format fail");
  
          return JNI_FALSE;
  
      }
  
  
  
      fmt_context->oformat = ofmt;
  
      LOGI("creating video stream");
  
      video_stream = av_new_stream(fmt_context, 0);
  
  
  
      if (enable_audio) {
  
          LOGI("creating audio stream");
  
          audio_stream = av_new_stream(fmt_context, 1);
  
      }
  
  
  
      // Open Video Codec.
  
      // ======================
  
      AVCodec *video_codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
      if (!video_codec) {
  
          LOGI("Did not find the video codec");
  
          return JNI_FALSE;  // leak!
  
      } else {
  
          LOGI("Video codec found!");
  
      }
  
      AVCodecContext *video_codec_ctx = video_stream->codec;
  
      video_codec_ctx->codec_id = video_codec->id;
  
      video_codec_ctx->codec_type = AVMEDIA_TYPE_VIDEO;
  
      video_codec_ctx->level = 31;
  
  
  
      video_codec_ctx->width = width;
  
      video_codec_ctx->height = height;
  
      video_codec_ctx->pix_fmt = PIX_FMT_YUV420P;
  
      video_codec_ctx->rc_max_rate = 0;
  
      video_codec_ctx->rc_buffer_size = 0;
  
      video_codec_ctx->gop_size = 12;
  
      video_codec_ctx->max_b_frames = 0;
  
      video_codec_ctx->slices = 8;
  
      video_codec_ctx->b_frame_strategy = 1;
  
      video_codec_ctx->coder_type = 0;
  
      video_codec_ctx->me_cmp = 1;
  
      video_codec_ctx->me_range = 16;
  
      video_codec_ctx->qmin = 10;
  
      video_codec_ctx->qmax = 51;
  
      video_codec_ctx->keyint_min = 25;
  
      video_codec_ctx->refs = 3;
  
      video_codec_ctx->trellis = 0;
  
      video_codec_ctx->scenechange_threshold = 40;
  
      video_codec_ctx->flags |= CODEC_FLAG_LOOP_FILTER;
  
      video_codec_ctx->me_method = ME_HEX;
  
      video_codec_ctx->me_subpel_quality = 6;
  
      video_codec_ctx->i_quant_factor = 0.71;
  
      video_codec_ctx->qcompress = 0.6;
  
      video_codec_ctx->max_qdiff = 4;
  
      video_codec_ctx->time_base.den = 10;
  
      video_codec_ctx->time_base.num = 1;
  
      video_codec_ctx->bit_rate = 3200 * 1000;
  
      video_codec_ctx->bit_rate_tolerance = 0;
  
      video_codec_ctx->flags2 |= 0x00000100;
  
  
  
      fmt_context->bit_rate = 4000 * 1000;
  
  
  
      av_opt_set(video_codec_ctx, "partitions", "i8x8,i4x4,p8x8,b8x8", 0);
  
      av_opt_set_int(video_codec_ctx, "direct-pred", 1, 0);
  
      av_opt_set_int(video_codec_ctx, "rc-lookahead", 0, 0);
  
      av_opt_set_int(video_codec_ctx, "fast-pskip", 1, 0);
  
      av_opt_set_int(video_codec_ctx, "mixed-refs", 1, 0);
  
      av_opt_set_int(video_codec_ctx, "8x8dct", 0, 0);
  
      av_opt_set_int(video_codec_ctx, "weightb", 0, 0);
  
  
  
      if (fmt_context->oformat->flags &amp; AVFMT_GLOBALHEADER)
  
          video_codec_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
      LOGI("Opening video codec");
  
      AVDictionary *vopts = NULL;
  
      av_dict_set(&amp;vopts, "profile", "main", 0);
  
      //av_dict_set(&amp;vopts, "vprofile", "main", 0);
  
      av_dict_set(&amp;vopts, "rc-lookahead", 0, 0);
  
      av_dict_set(&amp;vopts, "tune", "film", 0);
  
      av_dict_set(&amp;vopts, "preset", "ultrafast", 0);
  
      av_opt_set(video_codec_ctx->priv_data, "tune", "film", 0);
  
      av_opt_set(video_codec_ctx->priv_data, "preset", "ultrafast", 0);
  
      av_opt_set(video_codec_ctx->priv_data, "tune", "film", 0);
  
      int open_res = avcodec_open2(video_codec_ctx, video_codec, &amp;vopts);
  
      if (open_res &lt; 0) {
  
          LOGI("Error opening video codec: %i", open_res);
  
          return JNI_FALSE;   // leak!
  
      }
  
  
  
      // Open Audio Codec.
  
      // ======================
  
  
  
      if (enable_audio) {
  
          AudioBuffer_Clear();
  
          audio_sample_rate = audio_sample_rate_param;
  
          AVCodec *audio_codec = avcodec_find_encoder(AV_CODEC_ID_AAC);
  
          if (!audio_codec) {
  
              LOGI("Did not find the audio codec");
  
              return JNI_FALSE;  // leak!
  
          } else {
  
              LOGI("Audio codec found!");
  
          }
  
          AVCodecContext *audio_codec_ctx = audio_stream->codec;
  
          audio_codec_ctx->codec_id = audio_codec->id;
  
          audio_codec_ctx->codec_type = AVMEDIA_TYPE_AUDIO;
  
          audio_codec_ctx->bit_rate = 128000;
  
          audio_codec_ctx->bit_rate_tolerance = 16000;
  
          audio_codec_ctx->channels = 1;
  
          audio_codec_ctx->profile = FF_PROFILE_AAC_LOW;
  
          audio_codec_ctx->sample_fmt = AV_SAMPLE_FMT_FLT;
  
          audio_codec_ctx->sample_rate = 44100;
  
  
  
          LOGI("Opening audio codec");
  
          AVDictionary *opts = NULL;
  
          av_dict_set(&amp;opts, "strict", "experimental", 0);
  
          open_res = avcodec_open2(audio_codec_ctx, audio_codec, &amp;opts);
  
          LOGI("audio frame size: %i", audio_codec_ctx->frame_size);
  
  
  
          if (open_res &lt; 0) {
  
              LOGI("Error opening audio codec: %i", open_res);
  
              return JNI_FALSE;   // leak!
  
          }
  
      }
  
  
  
      const jbyte *url = (*env)->GetStringUTFChars(env, rtmp_url, NULL);
  
  
  
      // Point to an output file
  
      if (!(ofmt->flags &amp; AVFMT_NOFILE)) {
  
          if (avio_open(&amp;fmt_context->pb, url, URL_WRONLY) &lt; 0) {
  
              LOGI("ERROR: Could not open file %s", url);
  
              return JNI_FALSE;  // leak!
  
          }
  
      }
  
      (*env)->ReleaseStringUTFChars(env, rtmp_url, url);
  
  
  
      LOGI("Writing output header.");
  
      // Write file header
  
      if (avformat_write_header(fmt_context, NULL) != 0) {
  
          LOGI("ERROR: av_write_header failed");
  
          return JNI_FALSE;
  
      }
  
  
  
      pts = 0;
  
      last_audio_pts = 0;
  
      audio_samples_written = 0;
  
  
  
      // Initialize buffers for UV format conversion
  
      int frame_size = video_codec_ctx->width * video_codec_ctx->height;
  
      u_buf = (unsigned char *) av_malloc(frame_size / 4);
  
      v_buf = (unsigned char *) av_malloc(frame_size / 4);
  
  
  
      LOGI("ffmpeg encoding init done");
  
      return JNI_TRUE;
  
  }
  
  
  
  JNIEXPORT void JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_shutdown(JNIEnv
  
  *env,
  
  jobject thiz
  
  ) {
  
  av_write_trailer(fmt_context);
  
  avio_close(fmt_context
  
  ->pb);
  
  avcodec_close(video_stream
  
  ->codec);
  
  if (enable_audio) {
  
  avcodec_close(audio_stream
  
  ->codec);
  
  }
  
  av_free(fmt_context);
  
  av_free(u_buf);
  
  av_free(v_buf);
  
  
  
  fmt_context = NULL;
  
  u_buf = NULL;
  
  v_buf = NULL;
  
  }
  
  
  
  JNIEXPORT jint JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_encodeVideoFrame(JNIEnv
  
  *env,
  
  jobject thiz,
  
          jbyteArray
  
  yuv_image) {
  
  int yuv_length = (*env)->GetArrayLength(env, yuv_image);
  
  unsigned char *yuv_data = (*env)->GetByteArrayElements(env, yuv_image, 0);
  
  
  
  AVCodecContext *video_codec_ctx = video_stream->codec;
  
  //LOGI("Yuv size: %i w: %i h: %i", yuv_length, video_codec_ctx->width, video_codec_ctx->height);
  
  
  
  int frame_size = video_codec_ctx->width * video_codec_ctx->height;
  
  
  
  const unsigned char *uv = yuv_data + frame_size;
  
  
  
  // Convert YUV from NV12 to I420. Y channel is the same so we don't touch it,
  
  // we just have to deinterleave UV.
  
  for (
  
  int i = 0;
  
  i &lt; frame_size / 4; i++) {
  
  v_buf[i] = uv[i * 2];
  
  u_buf[i] = uv[i * 2 + 1];
  
  }
  
  
  
  AVFrame source;
  
  memset(&amp;source, 0, sizeof(AVFrame));
  
  source.data[0] =
  
  yuv_data;
  
  source.data[1] =
  
  u_buf;
  
  source.data[2] =
  
  v_buf;
  
  source.linesize[0] = video_codec_ctx->
  
  width;
  
  source.linesize[1] = video_codec_ctx->width / 2;
  
  source.linesize[2] = video_codec_ctx->width / 2;
  
  
  
  // only for bitrate regulation. irrelevant for sync.
  
  source.
  
  pts = pts;
  
  pts++;
  
  
  
  int out_length = frame_size + (frame_size / 2);
  
  unsigned char *out = (unsigned char *) av_malloc(out_length);
  
  int compressed_length = avcodec_encode_video(video_codec_ctx, out, out_length, &amp;source);
  
  
  
  (*env)->
  
  ReleaseByteArrayElements(env, yuv_image, yuv_data,
  
  0);
  
  
  
  // Write to file too
  
  if (compressed_length > 0) {
  
  AVPacket pkt;
  
  av_init_packet(&amp;pkt);
  
  pkt.
  
  pts = last_audio_pts;
  
  if (video_codec_ctx->coded_frame &amp;&amp; video_codec_ctx->coded_frame->key_frame) {
  
  pkt.flags |= 0x0001;
  
  }
  
  pkt.
  
  stream_index = video_stream->index;
  
  pkt.
  
  data = out;
  
  pkt.
  
  size = compressed_length;
  
  if (
  
  av_interleaved_write_frame(fmt_context,
  
  &amp;pkt) != 0) {
  
  LOGI("Error writing video frame");
  
  }
  
  } else {
  
  LOGI("??? compressed_length &lt;= 0");
  
  }
  
  
  
  last_audio_pts++;
  
  
  
  av_free(out);
  
  return
  
  compressed_length;
  
  }
  
  
  
  JNIEXPORT jint JNICALL Java_com_ephronsystem_mobilizerapp_Ffmpeg_encodeAudioFrame(JNIEnv
  
  *env,
  
  jobject thiz,
  
          jshortArray
  
  audio_data,
  
  jint length
  
  ) {
  
  if (!enable_audio) {
  
  return 0;
  
  }
  
  
  
  short *audio = (*env)->GetShortArrayElements(env, audio_data, 0);
  
  //LOGI("java audio buffer size: %i", length);
  
  
  
  AVCodecContext *audio_codec_ctx = audio_stream->codec;
  
  
  
  unsigned char *out = av_malloc(128000);
  
  
  
  AudioBuffer_Push(audio, length
  
  );
  
  
  
  int total_compressed = 0;
  
  while (
  
  
  
  AudioBuffer_Size()
  
  
  
  >= audio_codec_ctx->frame_size) {
  
  AVPacket pkt;
  
  av_init_packet(&amp;pkt);
  
  
  
  int compressed_length = avcodec_encode_audio(audio_codec_ctx, out, 128000,
  
                                               AudioBuffer_Get());
  
  
  
  total_compressed +=
  
  compressed_length;
  
  audio_samples_written += audio_codec_ctx->
  
  frame_size;
  
  
  
  int new_pts = (audio_samples_written * 1000) / audio_sample_rate;
  
  if (compressed_length > 0) {
  
  pkt.
  
  size = compressed_length;
  
  pkt.
  
  pts = new_pts;
  
  last_audio_pts = new_pts;
  
  //LOGI("audio_samples_written: %i  comp_length: %i   pts: %i", (int)audio_samples_written, (int)compressed_length, (int)new_pts);
  
  pkt.flags |= 0x0001;
  
  pkt.
  
  stream_index = audio_stream->index;
  
  pkt.
  
  data = out;
  
  if (
  
  av_interleaved_write_frame(fmt_context,
  
  &amp;pkt) != 0) {
  
  LOGI("Error writing audio frame");
  
  }
  
  }
  
  AudioBuffer_Pop(audio_codec_ctx
  
  ->frame_size);
  
  }
  
  
  
  (*env)->
  
  ReleaseShortArrayElements(env, audio_data, audio,
  
  0);
  
  
  
  av_free(out);
  
  return
  
  total_compressed;
  
  }

• Interlace two videos by alternating frames

  31 mars 2017, par GIRISH RAMNANI

  I am trying to interlace two videos by alternating frames. i.e. show a frame of the first video for 0.03s and then of the second for 0.03s. finally storing this into a file. I searched online and found that ffmpeg filters can be used to do this. But i am open to any other methods as well.