title: ffmpeg: How can a MOV with transparent background be created?
body: <p>I'm trying - with no success at all - to convert the green pixels of a background into transparent ones and output the result as clip with ffmpeg. N.b. I do <em>not</em> want to lay the clip over anything; I'm not having a problem with that. What I want is a clip with transparent background for the OpenShot video editor (the chromakey filter of which doesn't work satisfyingly).</p>
  
  <p>What I have tried (amongst 1 zillion other things over the last 15 hrs.) was </p>
  
  <pre><code>ffmpeg.exe -i in.mov -vf chromakey=0x008001:0.115:0.0 -c:v qtrle out.mov
  </code></pre>
  
  <p>but the pixels simply would not be transparent. Seemingly, nothing happens. I reckon the filter is ok, because it works fine in a complex chain (overlaying a background image).</p>
  
  <p>The output of ffprompt -show_stream -show_format of out.mov is as follows:</p>
  
  <pre><code>[STREAM]
  index=0
  codec_name=qtrle
  codec_long_name=QuickTime Animation (RLE) video
  profile=unknown
  codec_type=video
  codec_time_base=1/30
  codec_tag_string=rle
  codec_tag=0x20656c72
  width=1920
  height=1080
  coded_width=1920
  coded_height=1080
  has_b_frames=0
  sample_aspect_ratio=1:1
  display_aspect_ratio=16:9
  pix_fmt=bgra
  level=-99
  color_range=N/A
  color_space=unknown
  color_transfer=unknown
  color_primaries=unknown
  chroma_location=unspecified
  field_order=progressive
  timecode=N/A
  refs=1
  id=N/A
  r_frame_rate=30/1
  avg_frame_rate=30/1
  time_base=1/15360
  start_pts=0
  start_time=0.000000
  duration_ts=54789
  duration=3.566992
  bit_rate=822383192
  max_bit_rate=N/A
  bits_per_raw_sample=N/A
  nb_frames=107
  nb_read_frames=N/A
  nb_read_packets=N/A
  DISPOSITION:default=1
  DISPOSITION:dub=0
  DISPOSITION:original=0
  DISPOSITION:comment=0
  DISPOSITION:lyrics=0
  DISPOSITION:karaoke=0
  DISPOSITION:forced=0
  DISPOSITION:hearing_impaired=0
  DISPOSITION:visual_impaired=0
  DISPOSITION:clean_effects=0
  DISPOSITION:attached_pic=0
  DISPOSITION:timed_thumbnails=0
  TAG:language=eng
  TAG:handler_name=DataHandler
  TAG:encoder=Lavc57.64.101 qtrle
  [/STREAM]
  [STREAM]
  index=1
  codec_name=aac
  codec_long_name=AAC (Advanced Audio Coding)
  profile=LC
  codec_type=audio
  codec_time_base=1/44100
  codec_tag_string=mp4a
  codec_tag=0x6134706d
  sample_fmt=fltp
  sample_rate=44100
  channels=2
  channel_layout=stereo
  bits_per_sample=0
  id=N/A
  r_frame_rate=0/0
  avg_frame_rate=0/0
  time_base=1/44100
  start_pts=926
  start_time=0.020998
  duration_ts=157481
  duration=3.570998
  bit_rate=132103
  max_bit_rate=132103
  bits_per_raw_sample=N/A
  nb_frames=153
  nb_read_frames=N/A
  nb_read_packets=N/A
  DISPOSITION:default=1
  DISPOSITION:dub=0
  DISPOSITION:original=0
  DISPOSITION:comment=0
  DISPOSITION:lyrics=0
  DISPOSITION:karaoke=0
  DISPOSITION:forced=0
  DISPOSITION:hearing_impaired=0
  DISPOSITION:visual_impaired=0
  DISPOSITION:clean_effects=0
  DISPOSITION:attached_pic=0
  DISPOSITION:timed_thumbnails=0
  TAG:language=eng
  TAG:handler_name=DataHandler
  [/STREAM]
  [FORMAT]
  filename=out.mov
  nb_streams=2
  nb_programs=0
  format_name=mov,mp4,m4a,3gp,3g2,mj2
  format_long_name=QuickTime / MOV
  start_time=0.000000
  duration=3.567000
  size=366708874
  bit_rate=822447712
  probe_score=100
  TAG:major_brand=qt
  TAG:minor_version=512
  TAG:compatible_brands=qt
  TAG:encoder=Lavf57.56.101
  [/FORMAT]
  </code></pre>
  
  <p>I have a "sample" clip which shows the behaviour I want, with the following stream and information:</p>
  
  <pre><code>[STREAM]
  index=0
  codec_name=qtrle
  codec_long_name=QuickTime Animation (RLE) video
  profile=unknown
  codec_type=video
  codec_time_base=1/24
  codec_tag_string=rle
  codec_tag=0x20656c72
  width=1920
  height=1080
  coded_width=1920
  coded_height=1080
  has_b_frames=0
  sample_aspect_ratio=0:1
  display_aspect_ratio=0:1
  pix_fmt=bgra
  level=-99
  color_range=N/A
  color_space=unknown
  color_transfer=unknown
  color_primaries=unknown
  chroma_location=unspecified
  field_order=progressive
  timecode=N/A
  refs=1
  id=N/A
  r_frame_rate=24/1
  avg_frame_rate=24/1
  time_base=1/12288
  start_pts=0
  start_time=0.000000
  duration_ts=74760
  duration=6.083984
  bit_rate=49226848
  max_bit_rate=N/A
  bits_per_raw_sample=N/A
  nb_frames=146
  nb_read_frames=N/A
  nb_read_packets=N/A
  DISPOSITION:default=1
  DISPOSITION:dub=0
  DISPOSITION:original=0
  DISPOSITION:comment=0
  DISPOSITION:lyrics=0
  DISPOSITION:karaoke=0
  DISPOSITION:forced=0
  DISPOSITION:hearing_impaired=0
  DISPOSITION:visual_impaired=0
  DISPOSITION:clean_effects=0
  DISPOSITION:attached_pic=0
  DISPOSITION:timed_thumbnails=0
  TAG:language=eng
  TAG:handler_name=DataHandler
  TAG:encoder=Lavc57.24.102 qtrle
  [/STREAM]
  [STREAM]
  index=1
  codec_name=aac
  codec_long_name=AAC (Advanced Audio Coding)
  profile=LC
  codec_type=audio
  codec_time_base=1/48000
  codec_tag_string=mp4a
  codec_tag=0x6134706d
  sample_fmt=fltp
  sample_rate=48000
  channels=2
  channel_layout=stereo
  bits_per_sample=0
  id=N/A
  r_frame_rate=0/0
  avg_frame_rate=0/0
  time_base=1/48000
  start_pts=0
  start_time=0.000000
  duration_ts=293856
  duration=6.122000
  bit_rate=53537
  max_bit_rate=128000
  bits_per_raw_sample=N/A
  nb_frames=288
  nb_read_frames=N/A
  nb_read_packets=N/A
  DISPOSITION:default=1
  DISPOSITION:dub=0
  DISPOSITION:original=0
  DISPOSITION:comment=0
  DISPOSITION:lyrics=0
  DISPOSITION:karaoke=0
  DISPOSITION:forced=0
  DISPOSITION:hearing_impaired=0
  DISPOSITION:visual_impaired=0
  DISPOSITION:clean_effects=0
  DISPOSITION:attached_pic=0
  DISPOSITION:timed_thumbnails=0
  TAG:language=eng
  TAG:handler_name=DataHandler
  [/STREAM]
  [FORMAT]
  filename=templateOK.mov
  nb_streams=2
  nb_programs=0
  format_name=mov,mp4,m4a,3gp,3g2,mj2
  format_long_name=QuickTime / MOV
  start_time=0.000000
  duration=6.144000
  size=37478506
  bit_rate=48800138
  probe_score=100
  TAG:major_brand=qt
  TAG:minor_version=512
  TAG:compatible_brands=qt
  TAG:encoder=Lavf57.25.100
  [/FORMAT]
  </code></pre>
  
  <p>and I simply am not able to spot the relevant difference.</p>
  
  <p>The input, output and the working template can be found <a href="https://www.wot.at/owncloud/index.php/s/KRmtBt3a2J7zDCt" rel="nofollow noreferrer">here</a>.</p>
  
  <p>(The security issue you might see when clicking the link comes from the server certificate being self-signed. You can accept a temporal exception. Btw: The ridiculous file size of the output file will be the next nut to crack. Probably something about compression.)</p>