Roku Developer Program

[pbrentyoung]

We have a private channel with mp4 files. Everything plays beautifully with the Roku 1 but on the Roku 2 the higher bit rate files play out of sync and studder. Can someone give me some direction as to what direction to look to fix this problem.

Thanks for your help

[stratcat96]

"pbrentyoung" wrote:
We have a private channel with mp4 files. Everything plays beautifully with the Roku 1 but on the Roku 2 the higher bit rate files play out of sync and studder. Can someone give me some direction as to what direction to look to fix this problem.

Thanks for your help

I posted a thread in the regular Roku Streaming Player forum about higher bitrate MP4s not playing correctly through the Roku 2 XS's usb port after a fast forward or rewind. Those same files play fine on the Roku XDS's (Roku 1) USB port. Incidentally there has been some issues with local file support and the Roku 2 which caused Roku to temporarily remove support for MKV, WMV, and MOV files while they work out a fix. At this point I'm assuming the higher bitrate MP4 playback issue is another symptom of that same problem. At this point in time, all you may be able to do is re-encode to a lower bitrate but that may not be feasible

[Anonymous]

Can you dump the encoding details of the files you have having trouble playing and post them here? We'll try to create similarly encoded files to test with and hopefully reproduce the problems.

Thanks.

[stratcat96]

"RokuJon" wrote:
Can you dump the encoding details of the files you have having trouble playing and post them here? We'll try to create similarly encoded files to test with and hopefully reproduce the problems.

Thanks.

Jon, here's the encoding data of one of the files that will not play correctly on the R2 but will on the R1. As I said, it loads fine but will not re-load and play after a ff or rewind with the R2. The overall bitrate is 2748 Kbps, while the bitrate of files that work w/o problems on the R2 generally are sub 1900kbs. It's not quite the same problem as the OP but could very well be part of the same issue.

Format : MPEG-4
Format profile : Base Media
Codec ID : isom
File size : 353 MiB
Duration : 17mn 57s
Overall bit rate : 2 748 Kbps
Writing application : Lavf52.18.0
Comment : FlixEngineLinux_8.0.12.0 (http://www.on2.com)

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L3.1
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 18mn 45s
Bit rate mode : Variable
Bit rate : 2 502 Kbps
Width : 720 pixels
Height : 540 pixels
Display aspect ratio : 4:3
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Stream size : 336 MiB (95%)

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 17mn 57s
Bit rate mode : Variable
Bit rate : 128 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz
Compression mode : Lossy
Stream size : 16.4 MiB (5%)

[pbrentyoung]

I'm having issues with any files at a lower bit rate than that. I'm still having issues with files at 1K

NTSC
1280x720
29.97 progressive
Main 4.0
CBR 1Mps
33 frame keyframe distance

Audio
AAC, Stereo, 44.1
Audio Quality High
Bitrate: 192
Precedence: Frequency

Using PPro 5.5 for the render.

Thanks for being on this.

Also, if I switch to Amazon S3 is it going to solve the issues?

[Anonymous]

CBR 1Mps

You should switch to VBR which will work much better on our platform. CBR often results in padded frames that can cause a lot of problems.

Stratcat - nothing jumps out at me in your encoding details as particularly problematic. I'll have our internal QA team create some similar encodings and take a look.

Thanks!

[pbrentyoung]

In doing some tests, it seems that around 700K is the cutoff for streaming to play well over Roku2, haven't found any combination higher than that that plays well. Is anyone having success streaming mp4 files at higher bandwidth?

[stratcat96]

"RokuJon" wrote:

CBR 1Mps

You should switch to VBR which will work much better on our platform. CBR often results in padded frames that can cause a lot of problems.

Stratcat - nothing jumps out at me in your encoding details as particularly problematic. I'll have our internal QA team create some similar encodings and take a look.

Thanks!

Thanks Jon! As a test I re-encoded one of those higher bitrate vids using Freemake to the "Apple" preset and it just brought the bitrate down (and obviously the filesize) and it then played without a hiccup on the R2.

[destruk]

So for video, VBR is better, but for audio, CBR is better? With a VBR MP3 file you can't tell what the file length is without using the roAudioMetaData (which only works with local files). Can you clarify that please?

[pbrentyoung]

Creative Cow has a pretty good explanation of the difference.

http://forums.creativecow.net/thread/24/893298