Channel Issues & Questions

Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
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flynt7111
Level 7

Seek in MP4 video but the video always start from the beginning

Hi. I have a problem when seeking while playing an MP4 file. The video always restart at the beginning instead of the seek position.
I also try on the Roku Stream Tester channel and the result is the same. So, I think the problem is coming from the video. But, I couldn't find what's wrong with the MP4 file.

I did a little research and some mentioned it could be due to the video transcoding not support by Roku (https://forums.roku.com/viewtopic.php?t=88152)
1. Roku only has a limited codec set that it supports so a number of formats will have to be transcoded to play.
The following media file formats are supported:
Video — MKV (H.264), MP4 (H.264), MOV (H.264), WMV (VC-1, firmware 3.1 only)
Music — AAC, MP3, WMA, FLAC (firmware 5.3 and later), WAV (firmware 5.3 and later)
Photo — JPG, PNG, GIF (non-animated)
Only supported file types are shown in the Roku Media Player channel. The channel hides unsupported file types. Dolby Digital audio in MKV and MP4 movies is only supported via pass through.
DTS in MKV movies is also only supported via pass through. You must connect your Roku player via HDMI to a TV or receiver capable of decoding Dolby Digital or DTS in order to hear videos with audio tracks in those formats.
Some media server software may convert files into Roku compatible formats.
DRM-protected content is not supported

2. Files that are not directly supported will require transcoding and transcoding is very processor intensive so the server needs to have good power if files are to be transcoded. " - Elijah_Baley

However, my MP4 file is H264 and AAC encoded, so it should be supported by Roku device. Please check the link (https://ibb.co/hq61oz) for more details.
My MP4 file duration is about 12 seconds.

Does anyone have similar issues or know what cause have cause this issue?

* Updated:
I used another sample MP4 stream (https://www.sample-videos.com/video/mp4 ... 0p_5mb.mp4) which has duration 29s.
When I seek from 1 to 8s on Roku, it always rewind at the 0s point.
When I seek from 9 - 12s on Roku, it always rewind at 9s point. 
and so on.

So, could this be the issue with keyframe in MP4 file?

Thanks in advance.
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3 Replies
atc98092
Level 13

Re: Seek in MP4 video but the video always start from the beginning

How are you streaming the video, from a DLNA server or is it on a USB drive? If from DLNA, your server is probably transcoding. The question is, does the file need transcoding? Is your audio AAC stereo, or is it 5.1? Roku doesn't support 5.1 AAC. From the Roku media support page:


Support for AAC (Advanced Audio Coding)
Roku devices do not support AAC pass-through. Instead, Stereo AAC is transcoded to PCM stereo.

Roku TVs and some Roku players decode 5.1 AAC to PCM stereo for headphone, internal speaker, and HDMI/ S/PDIF (optical) output. However, Roku devices that support Dolby Audio decode connected via HDMI or S/PDIF (optical) to an A/V receiver that also supports Dolby Audio, will convert the audio to Dolby Digital 5.1.

Very few devices will decode 5.1 AAC to PCM stereo, so most likely yours does not. 
.
If you are playing the file from a USB drive, then there's no transcoding, because the Roku doesn't transcode video or audio. It has to be transcoded by an external device. If you're playing via USB, see if you can get the media info for your file, so we know exactly the codecs involved. 
Dan
Nvidia Shield, Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.
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flynt7111
Level 7

Re: Seek in MP4 video but the video always start from the beginning

Thanks atc98092.

My MP4 link is coming from a CDN network. The audio AAC is stereo and not 5.1.

I just found out that Roku only seeks to the key frame in my MP4 video. 
Example: the 2nd key frame of the video is using from 00:03s to 00:10s. If I seek any where between 00:03s - 00:10s, Roku always start to resume at 00:03s point.

So, If my video has 4 key frames, there will be <= 4 places that Roku will be resumed to in the entire video.

I am not sure if this is a Roku limitation or is there any other issue with my MP4.

Thanks
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atc98092
Level 13

Re: Seek in MP4 video but the video always start from the beginning

Ah, really getting into the technical issues. Good to know. RokuDale might be able to help here, as he's the main man for the Roku Media Player. 
Dan
Nvidia Shield, Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.
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