Recherche avancée

Sur d’autres sites (9057)

• opusdsp : adjust and optimize C function to match assembly

  15 août 2019, par Lynne

  opusdsp : adjust and optimize C function to match assembly
  The C and asm versions behaved differently _outside_ of the codec.
  The C version returned pre-multiplied 'state' for the next execution
  
  to use right away, while the assembly version outputted non-multiplied
  
  'state' for the next execution to multiply to save instructions.
  
  Since the initial state when initialized or seeking is always 0,
  
  and since C and asm versions were never mixed, there was no issue.
  However, comparing outputs directly in checkasm doesn't work without
  
  dividing the initial state by CELT_EMPH_COEFF and multiplying the
  
  returned state by CELT_EMPH_COEFF for the assembly function.
  Since its actually faster to do this in C as well, copy the behavior the
  
  asm versions use. As a reminder, the initial state 0 is divided by
  
  CELT_EMPH_COEFF on seek and init (just in case in the future this is
  
  changed, its technically more correct to init with CELT_EMPH_COEFF than 0,
  
  however when seeking this will result in more audiable pops, unlike with 0
  
  where the output gets in sync over a few samples).
  

  • [DH] libavcodec/opus_celt.c
  • [DH] libavcodec/opusdsp.c

• How to properly pass an asset FileDescriptor to FFmpeg using JNI in Android

  15 juillet 2014, par William Seemann

  I’m trying to retrieve metadata in Android using FFmpeg, JNI and a Java FileDescriptor and it isn’t’ working. I know FFmpeg supports the pipe protocol so I’m trying to emmulate : "cat test.mp3 | ffmpeg i pipe:0" programmatically. I use the following code to get a FileDescriptor from an asset bundled with the Android application :

  FileDescriptor fd = getContext().getAssets().openFd("test.mp3").getFileDescriptor();
  
  setDataSource(fd, 0, 0x7ffffffffffffffL); // native function, shown below

  Then, in my native (In C++) code I get the FileDescriptor by calling :

  static void wseemann_media_FFmpegMediaMetadataRetriever_setDataSource(JNIEnv *env, jobject thiz, jobject fileDescriptor, jlong offset, jlong length)
  
  {
  
      //...
  
  
  
      int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); // function contents show below
  
  
  
      //...
  
  }
  
  
  
  // function contents
  
  static int jniGetFDFromFileDescriptor(JNIEnv * env, jobject fileDescriptor) {
  
      jint fd = -1;
  
      jclass fdClass = env->FindClass("java/io/FileDescriptor");
  
  
  
      if (fdClass != NULL) {
  
          jfieldID fdClassDescriptorFieldID = env->GetFieldID(fdClass, "descriptor", "I");
  
          if (fdClassDescriptorFieldID != NULL && fileDescriptor != NULL) {
  
              fd = env->GetIntField(fileDescriptor, fdClassDescriptorFieldID);
  
          }
  
      }
  
  
  
      return fd;
  
  }

  I then pass the file descriptor pipe # (In C) to FFmpeg :

  char path[256] = "";
  
  
  
  FILE *file = fdopen(fd, "rb");
  
  
  
  if (file && (fseek(file, offset, SEEK_SET) == 0)) {
  
      char str[20];
  
      sprintf(str, "pipe:%d", fd);
  
      strcat(path, str);
  
  }
  
  
  
  State *state = av_mallocz(sizeof(State));
  
  state->pFormatCtx = NULL;
  
  
  
  if (avformat_open_input(&amp;state->pFormatCtx, path, NULL, &amp;options) != 0) { // Note: path is in the format "pipe:<the fd="fd">"
  
      printf("Metadata could not be retrieved\n");
  
      *ps = NULL;
  
      return FAILURE;
  
  }
  
  
  
  if (avformat_find_stream_info(state->pFormatCtx, NULL) &lt; 0) {
  
      printf("Metadata could not be retrieved\n");
  
      avformat_close_input(&amp;state->pFormatCtx);
  
      *ps = NULL;
  
      return FAILURE;
  
  }
  
  
  
  // Find the first audio and video stream
  
  for (i = 0; i &lt; state->pFormatCtx->nb_streams; i++) {
  
      if (state->pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO &amp;&amp; video_index &lt; 0) {
  
          video_index = i;
  
      }
  
  
  
      if (state->pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO &amp;&amp; audio_index &lt; 0) {
  
          audio_index = i;
  
      }
  
  
  
      set_codec(state->pFormatCtx, i);
  
  }
  
  
  
  if (audio_index >= 0) {
  
      stream_component_open(state, audio_index);
  
  }
  
  
  
  if (video_index >= 0) {
  
      stream_component_open(state, video_index);
  
  }
  
  
  
  printf("Found metadata\n");
  
  AVDictionaryEntry *tag = NULL;
  
  while ((tag = av_dict_get(state->pFormatCtx->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
  
      printf("Key %s: \n", tag->key);
  
      printf("Value %s: \n", tag->value);
  
  }
  
  
  
  *ps = state;
  
  return SUCCESS;
  
  </the>

  My issue is avformat_open_input doesn’t fail but it also doesn’t let me retrieve any metadata or frames, The same code works if I use a regular file URI (e.g file ://sdcard/test.mp3) as the path. What am I doing wrong ? Thanks in advance.

  Note : if you would like to look at all of the code I’m trying to solve the issue in order to provide this functionality for my library : FFmpegMediaMetadataRetriever.

• How to properly pass an asset FileDescriptor to FFmpeg using JNI in Android

  6 janvier 2021, par William Seemann

  I'm trying to retrieve metadata in Android using FFmpeg, JNI and a Java FileDescriptor and it isn't' working. I know FFmpeg supports the pipe protocol so I'm trying to emmulate : "cat test.mp3 | ffmpeg i pipe:0" programmatically. I use the following code to get a FileDescriptor from an asset bundled with the Android application :

  



  FileDescriptor fd = getContext().getAssets().openFd("test.mp3").getFileDescriptor();
setDataSource(fd, 0, 0x7ffffffffffffffL); // native function, shown below


  



  Then, in my native (In C++) code I get the FileDescriptor by calling :

  



  static void wseemann_media_FFmpegMediaMetadataRetriever_setDataSource(JNIEnv *env, jobject thiz, jobject fileDescriptor, jlong offset, jlong length)
{
    //...

    int fd = jniGetFDFromFileDescriptor(env, fileDescriptor); // function contents show below

    //...
}

// function contents
static int jniGetFDFromFileDescriptor(JNIEnv * env, jobject fileDescriptor) {
    jint fd = -1;
    jclass fdClass = env->FindClass("java/io/FileDescriptor");

    if (fdClass != NULL) {
        jfieldID fdClassDescriptorFieldID = env->GetFieldID(fdClass, "descriptor", "I");
        if (fdClassDescriptorFieldID != NULL && fileDescriptor != NULL) {
            fd = env->GetIntField(fileDescriptor, fdClassDescriptorFieldID);
        }
    }

    return fd;
}


  



  I then pass the file descriptor pipe # (In C) to FFmpeg :

  



  char path[256] = "";&#xA;&#xA;FILE *file = fdopen(fd, "rb");&#xA;&#xA;if (file &amp;&amp; (fseek(file, offset, SEEK_SET) == 0)) {&#xA;    char str[20];&#xA;    sprintf(str, "pipe:%d", fd);&#xA;    strcat(path, str);&#xA;}&#xA;&#xA;State *state = av_mallocz(sizeof(State));&#xA;state->pFormatCtx = NULL;&#xA;&#xA;if (avformat_open_input(&amp;state->pFormatCtx, path, NULL, &amp;options) != 0) { // Note: path is in the format "pipe:<the fd="fd">"&#xA;    printf("Metadata could not be retrieved\n");&#xA;    *ps = NULL;&#xA;    return FAILURE;&#xA;}&#xA;&#xA;if (avformat_find_stream_info(state->pFormatCtx, NULL) &lt; 0) {&#xA;    printf("Metadata could not be retrieved\n");&#xA;    avformat_close_input(&amp;state->pFormatCtx);&#xA;    *ps = NULL;&#xA;    return FAILURE;&#xA;}&#xA;&#xA;// Find the first audio and video stream&#xA;for (i = 0; i &lt; state->pFormatCtx->nb_streams; i&#x2B;&#x2B;) {&#xA;    if (state->pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO &amp;&amp; video_index &lt; 0) {&#xA;        video_index = i;&#xA;    }&#xA;&#xA;    if (state->pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO &amp;&amp; audio_index &lt; 0) {&#xA;        audio_index = i;&#xA;    }&#xA;&#xA;    set_codec(state->pFormatCtx, i);&#xA;}&#xA;&#xA;if (audio_index >= 0) {&#xA;    stream_component_open(state, audio_index);&#xA;}&#xA;&#xA;if (video_index >= 0) {&#xA;    stream_component_open(state, video_index);&#xA;}&#xA;&#xA;printf("Found metadata\n");&#xA;AVDictionaryEntry *tag = NULL;&#xA;while ((tag = av_dict_get(state->pFormatCtx->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {&#xA;    printf("Key %s: \n", tag->key);&#xA;    printf("Value %s: \n", tag->value);&#xA;}&#xA;&#xA;*ps = state;&#xA;return SUCCESS;&#xA;</the>

  



  My issue is avformat_open_input doesn't fail but it also doesn't let me retrieve any metadata or frames, The same code works if I use a regular file URI (e.g file ://sdcard/test.mp3) as the path. What am I doing wrong ? Thanks in advance.

  



  Note : if you would like to look at all of the code I'm trying to solve the issue in order to provide this functionality for my library : FFmpegMediaMetadataRetriever.