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>> Can't play MP4 / FLV Downloaded from YouTube (MPEG-DASH Support)

Many GOM Media Player users utilize third party download tools and browser plugins to download videos from websites like YouTube. Recently, many users are running into issues playing downloaded files with GOM Media Player, particularly those downloaded from YouTube, even though they could download and play the files with no problems before.

In most cases, these playback issues are the result of YouTube (and other websites) implementing a new type of media streaming technology called MPEG-DASH. You can read more about MPEG-DASH here:

Many download utilities are currently unable to properly handle MPEG-DASH, and the files that are downloaded essentially end up being incomplete. Because these files are incomplete, they cannot be played properly with GOM Media Player or other media playback software (sometimes only sound will be played, sometimes only video, and sometimes neither can be played).

If you try to play an MP4 or FLV file downloaded from YouTube and the Codec Finder window appears, please click the [Show Details] button to view the media info / binary info. If the info displayed is one of the following types, it can be assumed that the downloaded file was originally streamed using MPEG-DASH and could not be downloaded properly by the utility that was used.

Type 1:

FileName : FileName.mp4
Header Data : 
00 00 00 1c 66 74 79 70 64 61 73 68 00 00 00 00 ....ftypdash....
69 73 6f 36 61 76 63 31 6d 70 34 31 00 00 02 a8 iso6avc1mp41....
6d 6f 6f 76 00 00 00 6c 6d 76 68 64 00 00 00 00 moov...lmvhd....

Type 2:

majortype: MEDIATYPE_Stream {E436EB83-524F-11CE-9F53-0020AF0BA770}
subtype: Unknown GUID Name {08E22ADA-B715-45ED-9D20-7B87750301D4}
formattype: TIME_FORMAT_NONE {00000000-0000-0000-0000-000000000000}
bFixedSizeSamples: 1
bTemporalCompression: 0
lSampleSize: 1
cbFormat: 0

Unfortunately in these cases it will be impossible to play the file using GOM Media Player. 
* As of version video data can viewed when playing these files, but audio data cannot.

If you are running into issues downloading MPEG-DASH videos, we suggest that you try a different download utility or contact the developer of the utility you are using to ask them about MPEG-DASH support.

Please note that not all videos on YouTube are streamed using MPEG-DASH, so you may still be able to download and play some videos normally.

If you have additional questions regarding this issue, please don't hesitate to contact us via the GOM Media Player Support Center.

GOM Picker and MPEG-DASH:

GOM Picker was updated to version along with the GOM Video Converter update on August 7, 2013. 
As of this update GOM Picker is able to correctly download the majority of videos that previously could not be downloaded properly due to the MPEG-DASH issue.
This functionality is in beta form, however, and it is possible that the issue will persist for some videos. The development will continue to work to improve this feature.

GOM Picker comes as part of the GOM Video Converter installer, which can be downloaded for free here:

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