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• Compiling ffmpeg for iOS and gas-preprocessor.pl

  16 mai 2017, par user500

  I want to compile ffmpeg for iOS. I did it a few times before. But now I’m on clean new Mavericks and on configure I’m always getting

  Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
  
  Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
  
  GNU assembler not found, install gas-preprocessor
  
  
  
  If you think configure made a mistake, make sure you are using the latest
  
  version from Git.  If the latest version fails, report the problem to the
  
  ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
  
  Include the log file "config.log" produced by configure as this will help
  
  solving the problem.

  I have current Xcode installed. Also brews. And current gas-preprocessor.pl (https://github.com/yuvi/gas-preprocessor) in usr/bin and also in usr/local/bin.

  ---

  On perl /usr/bin/gas-preprocessor.pl gcc I’m getting Unrecognized input filetype at /usr/bin/gas-preprocessor.pl line 33.

  ---

  This config works :

  ./configure \
  
  --extra-cflags='-arch arm64 -mios-version-min=7.0 -mthumb' \
  
  --extra-ldflags='-arch arm64 -mios-version-min=7.0' \
  
  --enable-cross-compile \
  
  --arch=arm64 \
  
  --target-os=darwin \
  
  --cc=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang \
  
  --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk \
  
  --prefix=arm64 \
  
  --disable-doc \
  
  --disable-shared \
  
  --disable-everything \
  
  --enable-static \
  
  --enable-pic \
  
  --disable-muxers \
  
  --enable-muxer=flv \
  
  --disable-demuxers \
  
  --enable-demuxer=h264 \
  
  --enable-demuxer=pcm_s16le \
  
  --disable-devices \
  
  --disable-parsers \
  
  --enable-parser=h264 \
  
  --disable-encoders \
  
  --enable-encoder=aac \
  
  --disable-decoders \
  
  --enable-decoder=h264 \
  
  --enable-decoder=pcm_s16le \
  
  --disable-protocols \
  
  --enable-protocol=rtmp \
  
  --disable-filters \
  
  --disable-bsfs

  ---

  This config throws error above (GNU assembler not found, install gas-preprocessor) :

  ./configure \
  
  --cpu=cortex-a8 \
  
  --extra-cflags='-arch armv7 -mios-version-min=7.0 -mthumb' \
  
  --extra-ldflags='-arch armv7 -mios-version-min=7.0' \
  
  --enable-cross-compile \
  
  --arch=armv7 \
  
  --target-os=darwin \
  
  --cc=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang \
  
  --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk \
  
  --prefix=armv7 \
  
  --disable-doc \
  
  --disable-shared \
  
  --disable-everything \
  
  --enable-static \
  
  --enable-pic \
  
  --disable-muxers \
  
  --enable-muxer=flv \
  
  --disable-demuxers \
  
  --enable-demuxer=h264 \
  
  --enable-demuxer=pcm_s16le \
  
  --disable-devices \
  
  --disable-parsers \
  
  --enable-parser=h264 \
  
  --disable-encoders \
  
  --enable-encoder=aac \
  
  --disable-decoders \
  
  --enable-decoder=h264 \
  
  --enable-decoder=pcm_s16le \
  
  --disable-protocols \
  
  --enable-protocol=rtmp \
  
  --disable-filters \
  
  --disable-bsfs

• How to using every 5 sec generate video output File Path to Encode with RTMP Formate write data in ios ? [on hold]

  16 juillet 2015, par Sandeep Joshi

  (void) segmentRecording:(NSTimer*)timer {
  
  if (!shouldBeRecording) {
  
      [timer invalidate];
  
  }
  
  AVAssetWriter *tempAssetWriter = self.assetWriter;
  
  AVAssetWriterInput *tempAudioEncoder = self.audioEncoder;
  
  AVAssetWriterInput *tempVideoEncoder = self.videoEncoder;
  
  self.assetWriter = queuedAssetWriter;
  
  self.audioEncoder = queuedAudioEncoder;
  
  self.videoEncoder = queuedVideoEncoder;
  
  NSLog(@"Switching encoders");
  
  
  
  dispatch_async(segmentingQueue, ^{
  
      if (tempAssetWriter.status == AVAssetWriterStatusWriting) {
  
          @try {
  
              [tempAudioEncoder markAsFinished];
  
              [tempVideoEncoder markAsFinished];
  
              [tempAssetWriter finishWritingWithCompletionHandler:^{
  
                  if (tempAssetWriter.status == AVAssetWriterStatusFailed) {
  
                      [self showError:tempAssetWriter.error];
  
                  } else {
  
                      [self uploadLocalURL:tempAssetWriter.outputURL];
  
                  }
  
              }];
  
          }
  
          @catch (NSException *exception) {
  
              NSLog(@"Caught exception: %@", [exception description]);
  
              //[BugSenseController logException:exception withExtraData:nil];
  
          }
  
      }
  
      self.segmentCount++;
  
      if (self.readyToRecordAudio && self.readyToRecordVideo) {
  
          NSError *error = nil;
  
          self.queuedAssetWriter = [[AVAssetWriter alloc] initWithURL:[OWUtilities urlForRecordingSegmentCount:segmentCount basePath:self.basePath] fileType:(NSString *)kUTTypeMPEG4 error:&error];
  
          if (error) {
  
              [self showError:error];
  
          }
  
          self.queuedVideoEncoder = [self setupVideoEncoderWithAssetWriter:self.queuedAssetWriter formatDescription:videoFormatDescription bitsPerSecond:videoBPS];
  
          self.queuedAudioEncoder = [self setupAudioEncoderWithAssetWriter:self.queuedAssetWriter formatDescription:audioFormatDescription bitsPerSecond:audioBPS];
  
          //NSLog(@"Encoder switch finished");
  
      }
  
  });}
  
  
  
  
  
  
  
  (void) uploadLocalURL:(NSURL*)url {
  
  NSLog(@"upload local url: %@", url);
  
  NSString *inputPath = [url path];
  
  NSString *outputPath = [inputPath stringByReplacingOccurrencesOfString:@".mp4" withString:@".ts"];
  
  NSString *outputFileName = [outputPath lastPathComponent];
  
  NSDictionary *options = @{kFFmpegOutputFormatKey: @"mpegts"};
  
  NSLog(@"%@ conversion...", outputFileName);
  
  [ffmpegWrapper convertInputPath:[url path] outputPath:outputPath options:options progressBlock:nil completionBlock:^(BOOL success, NSError *error) {
  
      if (success) {
  
          if (!isRtmpConnected) {
  
              isRtmpConnected = [rtmp openWithURL:HOST_URL enableWrite:YES];
  
          }
  
          isRtmpConnected = [rtmp isConnected];
  
  
  
          if (isRtmpConnected) {
  
  
  
              NSData *video = [NSData dataWithContentsOfURL:[NSURL URLWithString:outputPath]];
  
              NSUInteger length = [video length];
  
              NSUInteger chunkSize = 1024 * 5;;
  
              NSUInteger offset = 0;
  
              NSLog(@"original video length: %lu \n chunkSize : %lu", length,chunkSize);
  
            // Let's split video to small chunks to publish to media server
  
              do {
  
                  NSUInteger thisChunkSize = length - offset > chunkSize ? chunkSize : length - offset;
  
                  NSData* chunk = [NSData dataWithBytesNoCopy:(char *)[video bytes] + offset
  
                                                       length:thisChunkSize
  
                                                 freeWhenDone:NO];
  
                  offset += thisChunkSize;
  
  
  
                  // Write new chunk to rtmp server
  
                  NSLog(@"%lu", (unsigned long)[rtmp write:chunk]);
  
                  sleep(1);
  
              } while (offset < length);
  
          }else{
  
              [rtmp close];
  
          }
  
  
  
  
  
      } else {
  
          NSLog(@"conversion error: %@", error.userInfo);
  
      }
  
  }];}

  This code use for live streaming for send data using RTMP Wrapper.
  Not write in Socket properly because every 5 second to generate different file output file.

  This is proper way ?

  I have no idea how to get NSData in proper way.

  Please help me .

• FFmpeg - MJPEG decoding gives inconsistent values

  28 décembre 2016, par ahmadh

  I have a set of JPEG frames which I am muxing into an avi, which gives me a mjpeg video. This is the command I run on the console :

  ffmpeg -y -start_number 0 -i %06d.JPEG -codec copy vid.avi

  When I try to demux the video using ffmpeg C api, I get frames which are slightly different in values. Demuxing code looks something like this :

  AVFormatContext* fmt_ctx = NULL;
  
  AVCodecContext* cdc_ctx = NULL;
  
  AVCodec* vid_cdc = NULL;
  
  int ret;
  
  unsigned int height, width;
  
  
  
  ....
  
  // read_nframes is the number of frames to read
  
  output_arr = new unsigned char [height * width * 3 * 
  
                                  sizeof(unsigned char) * read_nframes];
  
  
  
  avcodec_open2(cdc_ctx, vid_cdc, NULL);
  
  
  
  int num_bytes;
  
  uint8_t* buffer = NULL;
  
  const AVPixelFormat out_format = AV_PIX_FMT_RGB24;
  
  
  
  num_bytes = av_image_get_buffer_size(out_format, width, height, 1);
  
  buffer = (uint8_t*)av_malloc(num_bytes * sizeof(uint8_t));
  
  
  
  AVFrame* vid_frame = NULL;
  
  vid_frame = av_frame_alloc();
  
  AVFrame* conv_frame = NULL;
  
  conv_frame = av_frame_alloc();
  
  
  
  av_image_fill_arrays(conv_frame->data, conv_frame->linesize, buffer, 
  
                       out_format, width, height, 1);
  
  
  
  struct SwsContext *sws_ctx = NULL;
  
  sws_ctx = sws_getContext(width, height, cdc_ctx->pix_fmt,
  
                           width, height, out_format,
  
                           SWS_BILINEAR, NULL,NULL,NULL);
  
  
  
  int frame_num = 0;
  
  AVPacket vid_pckt;
  
  while (av_read_frame(fmt_ctx, &vid_pckt) >=0) {
  
      ret = avcodec_send_packet(cdc_ctx, &vid_pckt);
  
      if (ret < 0)
  
          break;
  
  
  
      ret = avcodec_receive_frame(cdc_ctx, vid_frame);
  
      if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
  
          break;
  
      if (ret >= 0) {
  
          // convert image from native format to planar GBR
  
          sws_scale(sws_ctx, vid_frame->data, 
  
                    vid_frame->linesize, 0, vid_frame->height, 
  
                    conv_frame->data, conv_frame->linesize);
  
  
  
          unsigned char* r_ptr = output_arr + 
  
              (height * width * sizeof(unsigned char) * 3 * frame_num);
  
          unsigned char* g_ptr = r_ptr + (height * width * sizeof(unsigned char));
  
          unsigned char* b_ptr = g_ptr + (height * width * sizeof(unsigned char));
  
          unsigned int pxl_i = 0;
  
  
  
          for (unsigned int r = 0; r < height; ++r) {
  
              uint8_t* avframe_r = conv_frame->data[0] + r*conv_frame->linesize[0];
  
              for (unsigned int c = 0; c < width; ++c) {
  
                  r_ptr[pxl_i] = avframe_r[0];
  
                  g_ptr[pxl_i]   = avframe_r[1];
  
                  b_ptr[pxl_i]   = avframe_r[2];
  
                  avframe_r += 3;
  
                  ++pxl_i;
  
              }
  
          }
  
  
  
          ++frame_num;
  
  
  
          if (frame_num >= read_nframes)
  
              break;
  
      }
  
  }
  
  
  
  ...

  In my experience around two-thirds of the pixel values are different, each by +-1 (in a range of [0,255]). I am wondering is it due to some decoding scheme FFmpeg uses for reading JPEG frames ? I tried encoding and decoding png frames, and it works perfectly fine. I am sure this is something to do with the libav decoding process because the MD5 values are consistent between the images and the video :

  ffmpeg -i %06d.JPEG -f framemd5 -
  
  ffmpeg -i vid.avi -f framemd5 -

  In short my goal is to get the same pixel by pixel values for each JPEG frame as I would I have gotten if I was reading the JPEG images directly. Here is the stand-alone bitbucket code I used. It includes cmake files to build code, and a couple of jpeg frames with the converted avi file to test this problem. (give ’—filetype png’ to test the png decoding).