[mythtv-users] Problem with MPEG-4 transcoded file (no bitrate or duration)
mythtv at kosowsky.org
mythtv at kosowsky.org
Mon May 13 04:12:01 UTC 2019
mythtv at kosowsky.org wrote at about 00:00:23 -0400 on Monday, May 13, 2019:
> In my old mythtv box (v24), I had no problem transcoding recordings to
> MPEG4 and then editing (i.e. cutting) the video in the mythtv editor.
>
> For example, a transcoded and edited file, shows up under ffmpeg -i
> as:
> Duration: 00:19:16.47, start: 0.033000, bitrate: 1411 kb/s
> Stream #0:0: Video: mpeg4 (Simple Profile) (DIVX / 0x58564944), yuv420p, 720x480 [SAR 1:1 DAR 3:2], SAR 32:27 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, 30k tbc
> Stream #0:1: Audio: mp3 (LAME / 0x454D414C), 48000 Hz, stereo, s16p, 1411 kb/s
>
> Under v29.1, when I transcode to mpeg4, the file seems to transcode (and compress) properly and I have no problem playing it.
> But, when I try to edit it, the timestamps are all wrong, so that when I use the editor to cut and re-transcode, the cut list is not properly applied and the file is not spliced together properly.
> When I run 'ffmpeg -i' I see that both the "Duration" and the "bitrate" are 'N/A', presumably explaining why the timestamps are wrong.
> Duration: N/A, start: 60704.885000, bitrate: N/A
> Stream #0:0: Video: mpeg4 (Simple Profile) (DIVX / 0x58564944), yuv420p, 704x480 [SAR 1:1 DAR 22:15], SAR 40:33 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, 30k tbc
> Stream #0:1: Audio: mp3 (LAME / 0x454D414C), 48000 Hz, stereo, s16p, 1411 kb/s
>
> I tried using 'mythcommflag --rebuild --file' to rebuild the seektable (which has saved me other times), but id had no effect.
>
> Is there something broken with mythtranscode that causes the file to create transcodings without defined durations or timestamps?
>
> Again, I never had the problem in (much) older version of mythtv...
>
> Thanks,
> Jeff
Note the transcoding profile I use is as follows:
Autodetect from MPEG2
Profile name: MPEG2
Enable auto-transcode after recording: yes
Width: 720
Height: 480
Video Compression: MPEG-4
Bitrate (kb/s): 3300
Maximum quality: 2
Minimum quality: 15
Max quality difference between frames: 3
Scale bitrate for frame size: No
Enable high-quality recording: Yes
Enable 4MV encoding: Yes
Enable interlaced DCT encoding: No
Enable interlaced motion estimation: No
Number of threads: 4
Audio Quality: MP3
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