[mythtv-users] Commercial Flagging after Transcode

HP-mini blm-ubunet at slingshot.co.nz
Mon Mar 14 18:56:55 UTC 2016


On Sun, 2016-03-13 at 13:37 -0500, Michael Wisniewski wrote:


> On Fri, Mar 11, 2016 at 1:22 PM, HP-mini <blm-ubunet at slingshot.co.nz>
> wrote:
>         On Fri, 2016-03-11 at 12:43 -0500, Daryl McDonald wrote:
>         > On Fri, Mar 11, 2016 at 11:40 AM, Michael Wisniewski
>         > <mikewiz38 at gmail.com> wrote:
>         >         On Thu, Mar 10, 2016 at 7:34 PM, Mark
>         >         <perkins1724 at hotmail.com> wrote:
>         >                 > -----Original Message-----
>         >                 > From: mythtv-users
>         >                 [mailto:mythtv-users-bounces at mythtv.org] On
>         Behalf
>         >                 > Of Michael Wisniewski
>         >                 > Sent: Friday,
>         
<snip>
>         >
>         If you transcode to AVCC format H264 mpeg PS (mpeg4 container)
>         you then
>         can not generate seektable (& then cutlist) & probably can't
>         meaningfully use mythcommflag.
>         
>         MythTV only generates seektables for H264 video in TS
>         container.
>         You need to modify the H264 transcode script to use annexB
>         H264 mpeg
>         transport stream container.
>         The other issues is that typical x264 settings has very sparse
>         keyframes
>         (potential cut points).
>         
>         The TS container file is a bit larger but is more robust.


> Thanks for the response.  So, it sounds like my problem is that I'm
> creating files that aren't fully compatible with myth.   I suppose I
> have some more research to do on this...  
> 
> 
> If I understand you correctly, the videos have to be in an "MPEG
> transport stream" and not in the mpeg4 container that I'm using.  
> 
> 
> Is there a reason myth doesn't move over to mpeg4, or something else?

AFAIK
Most video files are compatible with MythTV but only mpeg TS/PS with
mpeg2video & H264 (AVC mpeg part 10) annexB mpeg TS that can generate
seektables.
There is no parser for mpeg PS H264 in mythtv BE (ffmpeg independent).

AIUI
The mpeg2 TS & PS file formats are part of the mpeg4 standard.
Don't have / not read mpeg4 parts 12,14 or 15.

The only "something else" could be MKV? It still uses mov atom but is
meant to allow fast accurate seeking like TS files.

For DVB/ATSC & HDPVR, MythTV just parses & records what it receives.
Transport streams are used for all OTA broadcast TV & bluray, cameras
etc.
That said it is fairly trivial to re-mux (PS<>TS) with ffmpeg (always
easier said than done).

There is no benefit moving to PS files just less robust files (maybe 5%
size reduction).
The transport stream container is a little more restrictive on codec
choice (no mp3 which is a good thing).
The mpeg PS container (PS) is not ideal or practical for media streams;
uses concept of single mov atom & packet length data. 

Try changing the script to use "-f mpegts" & "-bsf:v h264_mp4toannexb"
The default settings for x264 will not give anything like broadcast
video stream tho.

But the android devices I've tried worked with H264 & AAC in TS
container (broadcast).



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