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• iOS GPUImage : which AVAssetWriter settings to match 'Constrained Baseline' h.264

  15 août 2014, par sunilr

  I have an iOS app which records video using GPUImage. These videos are stored remotely for viewing by other devices. I’d like the resulting video compression to match the settings which are commonly used in Instagram’s videos. I’ve inspected a number of instagram videos and running ffmpeg -i on them results in :

  Stream #0:0(und) : Video : h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 640x640 [SAR 1:1 DAR 1:1], 1104 kb/s, 29.97 fps, 29.97 tbr, 11988 tbn, 59.94 tbc (default)

  How should i match these ? The current settings i’m using are very close to the GPUImage defaults :

  NSDictionary *videoCleanApertureSettings = [NSDictionary dictionaryWithObjectsAndKeys:
  
                                              [NSNumber numberWithInt:videoSize.width], AVVideoCleanApertureWidthKey,
  
                                              [NSNumber numberWithInt:videoSize.height], AVVideoCleanApertureHeightKey,
  
                                              [NSNumber numberWithInt:0], AVVideoCleanApertureHorizontalOffsetKey,
  
                                              [NSNumber numberWithInt:0], AVVideoCleanApertureVerticalOffsetKey,
  
                                              nil];
  
  
  
  NSDictionary *videoAspectRatioSettings = [NSDictionary dictionaryWithObjectsAndKeys:
  
                                            [NSNumber numberWithInt:1], AVVideoPixelAspectRatioHorizontalSpacingKey,
  
                                            [NSNumber numberWithInt:1], AVVideoPixelAspectRatioVerticalSpacingKey,
  
                                            nil];
  
  
  
  NSMutableDictionary * compressionProperties = [[NSMutableDictionary alloc] init];
  
  [compressionProperties setObject:videoCleanApertureSettings forKey:AVVideoCleanApertureKey];
  
  [compressionProperties setObject:videoAspectRatioSettings forKey:AVVideoPixelAspectRatioKey];
  
  [compressionProperties setObject:[NSNumber numberWithInt: 1100000] forKey:AVVideoAverageBitRateKey];
  
  [compressionProperties setObject:[NSNumber numberWithInt: 16] forKey:AVVideoMaxKeyFrameIntervalKey];
  
  [compressionProperties setObject:AVVideoProfileLevelH264BaselineAutoLevel forKey:AVVideoProfileLevelKey];
  
  
  
  NSMutableDictionary *settings = [[NSMutableDictionary alloc] init];
  
  [settings setObject:AVVideoCodecH264 forKey:AVVideoCodecKey];
  
  [settings setObject:[NSNumber numberWithInt:videoSize.width] forKey:AVVideoWidthKey];
  
  [settings setObject:[NSNumber numberWithInt:videoSize.height] forKey:AVVideoHeightKey];
  
  [settings setObject:compressionProperties forKey:AVVideoCompressionPropertiesKey];

  But when i run ffmpeg -i on the videos created, i get :

  Stream #0:0(und) : Video : h264 (Baseline) (avc1 / 0x31637661), yuv420p, 480x480, 1128 kb/s, SAR 1:1 DAR 1:1, 23.86 fps, 24 tbr, 600 tbn, 1200 tbc (default)

  I’m not sure what the difference is between ’Baseline’ and ’Constrained Baseline’ is, so it may be that the settings i have are adequate (for playback of the video from a remote URL on a mobile device).

  Running an ffmpeg conversion on the file with : ffmpeg -i -profile:v baseline DOES recreate the instagram settings, but i’d like to have this happen on the device if possible.

• ituh263dec : Have function signature match across declaration and definition

  31 octobre 2016, par Diego Biurrun

  ituh263dec : Have function signature match across declaration and definition
  libavcodec/ituh263dec.c(215) : warning C4028 : formal parameter 1 different from declaration
  
  libavcodec/ituh263dec.c(215) : warning C4028 : formal parameter 2 different from declaration
  

  • [DBH] libavcodec/h263.h

• rtmp : Rename packet types to closer match the spec

  31 janvier 2017, par Martin Storsjö

  rtmp : Rename packet types to closer match the spec
  Also rename comments and log messages accordingly,
  
  and add clarifying comments for some hardcoded values.
  The previous names were taken from older, reverse engineered
  
  references.
  These names match the official public rtmp specification, and
  
  matches the names used by wirecast in annotating captured
  
  streams. These names also avoid hardcoding the roles of server
  
  and client, since the handling of them is irrelevant of whether
  
  we act as server or client.
  The RTMP_PT_PING type maps to RTMP_PT_USER_CONTROL.
  The SERVER_BW and CLIENT_BW types are a bit more intertwined ;
  
  RTMP_PT_SERVER_BW maps to RTMP_PT_WINDOW_ACK_SIZE and
  
  RTMP_PT_CLIENT_BW maps to RTMP_PT_SET_PEER_BW.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/rtmppkt.c
  • [DBH] libavformat/rtmppkt.h
  • [DBH] libavformat/rtmpproto.c