title: Android Mux mp4a and mp4
body: <p>I extracted a MPEG-DASH xml and i downloaded media urls manually and i have a mp4 video file and Audio file has saved separately into a mp4a file.<br>
  I want to merge this audio and video file into a single mp4 file.<br>
  I tried with MediaMuxer, But MediaExtractor does not know mp4a file.  </p>
  
  <p>I extracted files meta data info like codec, and other details in below.</p>
  
  <p>Audio file meta data info</p>
  
  <pre><code>MDItemAudioBitRate                = 48
  kMDItemAudioChannelCount           = 1
  kMDItemCodecs                      = (
      AAC
  )
  kMDItemContentCreationDate         = 2018-08-03 09:41:01 +0000
  kMDItemContentCreationDate_Ranking = 2018-08-03 00:00:00 +0000
  kMDItemContentModificationDate     = 2018-08-03 09:41:01 +0000
  kMDItemContentType                 = "public.mpeg-4"
  kMDItemContentTypeTree             = (
      "public.mpeg-4",
      "public.item",
      "public.movie",
      "public.audiovisual-content",
      "public.mpeg-4",
      "public.data",
      "public.content"
  )
  kMDItemDateAdded                   = 2018-08-03 09:41:01 +0000
  kMDItemDateAdded_Ranking           = 2018-08-03 00:00:00 +0000
  kMDItemDisplayName                 = "1533200401950_a.mp4"
  kMDItemDurationSeconds             = 1129.732
  kMDItemFSContentChangeDate         = 2018-08-03 09:41:01 +0000
  kMDItemFSCreationDate              = 2018-08-03 09:41:01 +0000
  kMDItemFSCreatorCode               = ""
  kMDItemFSFinderFlags               = 0
  kMDItemFSHasCustomIcon             = (null)
  kMDItemFSInvisible                 = 0
  kMDItemFSIsExtensionHidden         = 0
  kMDItemFSIsStationery              = (null)
  kMDItemFSLabel                     = 0
  kMDItemFSName                      = "1533200401950_a.mp4"
  kMDItemFSNodeCount                 = (null)
  kMDItemFSOwnerGroupID              = 20
  kMDItemFSOwnerUserID               = 501
  kMDItemFSSize                      = 7068402
  kMDItemFSTypeCode                  = ""
  kMDItemInterestingDate_Ranking     = 2018-08-03 00:00:00 +0000
  kMDItemKind                        = "MPEG-4 movie"
  kMDItemLastUsedDate                = 2018-08-03 11:18:56 +0000
  kMDItemLastUsedDate_Ranking        = 2018-08-03 00:00:00 +0000
  kMDItemLogicalSize                 = 7068402
  kMDItemMediaTypes                  = (
      Sound
  )
  kMDItemPhysicalSize                = 7069696
  kMDItemStreamable                  = 0
  kMDItemTotalBitRate                = 48
  kMDItemUseCount                    = 7
  kMDItemUsedDates                   = (
      "2018-08-02 19:30:00 +0000"
  )
  </code></pre>
  
  <p>Video meta data info :</p>
  
  <pre><code>kMDItemCodecs                      = (
      "H.264"
  )
  kMDItemContentCreationDate         = 2018-08-03 11:06:58 +0000
  kMDItemContentCreationDate_Ranking = 2018-08-03 00:00:00 +0000
  kMDItemContentModificationDate     = 2018-08-03 11:07:02 +0000
  kMDItemContentType                 = "public.mpeg-4"
  kMDItemContentTypeTree             = (
      "public.mpeg-4",
      "public.item",
      "public.movie",
      "public.audiovisual-content",
      "public.mpeg-4",
      "public.data",
      "public.content"
  )
  kMDItemDateAdded                   = 2018-08-03 11:06:58 +0000
  kMDItemDateAdded_Ranking           = 2018-08-03 00:00:00 +0000
  kMDItemDisplayName                 = "1533200401950_v.mp4"
  kMDItemDurationSeconds             = 1129.441
  kMDItemFSContentChangeDate         = 2018-08-03 11:07:02 +0000
  kMDItemFSCreationDate              = 2018-08-03 11:06:58 +0000
  kMDItemFSCreatorCode               = ""
  kMDItemFSFinderFlags               = 0
  kMDItemFSHasCustomIcon             = (null)
  kMDItemFSInvisible                 = 0
  kMDItemFSIsExtensionHidden         = 0
  kMDItemFSIsStationery              = (null)
  kMDItemFSLabel                     = 0
  kMDItemFSName                      = "1533200401950_v.mp4"
  kMDItemFSNodeCount                 = (null)
  kMDItemFSOwnerGroupID              = 20
  kMDItemFSOwnerUserID               = 501
  kMDItemFSSize                      = 107974918
  kMDItemFSTypeCode                  = ""
  kMDItemInterestingDate_Ranking     = 2018-08-03 00:00:00 +0000
  kMDItemKind                        = "MPEG-4 movie"
  kMDItemLastUsedDate                = 2018-08-03 11:07:06 +0000
  kMDItemLastUsedDate_Ranking        = 2018-08-03 00:00:00 +0000
  kMDItemLogicalSize                 = 107974918
  kMDItemMediaTypes                  = (
      Video
  )
  kMDItemPhysicalSize                = 117506048
  kMDItemPixelHeight                 = 704
  kMDItemPixelWidth                  = 396
  kMDItemStreamable                  = 0
  kMDItemTotalBitRate                = 762
  kMDItemUseCount                    = 1
  kMDItemUsedDates                   = (
      "2018-08-02 19:30:00 +0000"
  )
  kMDItemVideoBitRate                = 762
  </code></pre>
  
  <p>Please advice</p>