On 18/03/18 08:41, Mark Perkins wrote:
>
> On 03/03/18 23:32, Brian J. Murrell wrote:
>> I have been trying to use the IPTV recorder to record from a particular
>> HLS stream.
>>
>> The files resulting from this recording are on the order of 10GB per
>> hour, which is ridiculous. They also "jump" around while trying to
>> play them, even with something as generic as mplayer.
>>
>> I have used "ffmpeg -acodec copy -vcodec copy" to record from the exact
>> same m3u8 that I am giving to the IPTV recorder and I get something
>> more reasonably on the order of 1GB per hour and perfectly playable.
>>
>> I wonder if anyone else has experienced anything similar.
>>
>> I wonder if anyone has written an "external recorder" around ffmpeg as
>> a stream copier that they want to share as an alternative to the IPTV
>> recorder.
>>
>> Cheers,
>> b.
>>
> Have you tried using ffmpeg -i or mediainfo or something equivalent to
> compare the file created by mythtv to the file created from ffmpeg? I
> would be curious to know what was in the big file that was making it so big.
> _______________________________________________
>
Just to put some additional words around this. I use the IPTV recorder
functionality for my recordings. I have a box with USB DVB-T tuners
attached that runs mumudvb to rebroadcast the streams to multicast IP. I
can then subscribe to those streams from as many mythbackends as I like
simultaneously from anywhere on my network. I picked a SD recording from
the news last night which was 588MiB for 27min which is fairly
comparable to your 1GB per hour. So I don't think your large file sizes
are necessarily a problem with the IPTV recorder functionality but
perhaps related to what is specifically being transmitted in the stream.
Although I have no immediate suggestions as to what the IPTV recorder
functionality is including that is quite large in size but is excluded
by "ffmpeg -acodec copy -vcodec copy".
If I had to guess, based on your sizes, perhaps the IPTV recorder has
recorded an entire multiplex not just a specific channel / stream?
Mediainfo or ffmpeg on the file should reveal more.
Here are some stats from my news recording:
$ ls -alh 1002_20180317093300.ts
-rw-rw-r--. 1 mythtv mythtv 562M Mar 17 20:30 1002_20180317093300.ts
$ ffmpeg -i 1002_20180317093300.ts
ffmpeg version N-90289-g8fb0e51 Copyright (c) 2000-2018 the FFmpeg
developers
built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-16)
configuration: --prefix=/root/ffmpeg_build
--pkg-config-flags=--static --extra-cflags=-I/root/ffmpeg_build/include
--extra-ldflags=-L/root/ffmpeg_build/lib --extra-libs='-lm -lpthread'
--bindir=/usr/local/bin --enable-gpl --enable-libfdk_aac
--enable-libfreetype --enable-libmp3lame --enable-libopus
--enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
libavutil 56. 9.100 / 56. 9.100
libavcodec 58. 14.100 / 58. 14.100
libavformat 58. 10.100 / 58. 10.100
libavdevice 58. 2.100 / 58. 2.100
libavfilter 7. 13.100 / 7. 13.100
libswscale 5. 0.102 / 5. 0.102
libswresample 3. 0.101 / 3. 0.101
libpostproc 55. 0.100 / 55. 0.100
[mp3 @ 0x3f69840] Header missing
[mpegts @ 0x3f63980] PES packet size mismatch
[mpegts @ 0x3f63980] Could not find codec parameters for stream 3
(Unknown: none ([11][0][0][0] / 0x000B)): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize'
options
[mpegts @ 0x3f63980] Could not find codec parameters for stream 4
(Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize'
options
Input #0, mpegts, from '1002_20180317093300.ts':
Duration: 00:27:02.82, start: 9533.651444, bitrate: 2900 kb/s
Program 1
Stream #0:0[0x200]: Video: mpeg2video (Main) ([2][0][0][0] /
0x0002), yuv420p(tv, bt470bg, top first), 720x576 [SAR 64:45 DAR 16:9],
25 fps, 25 tbr, 90k tbn, 50 tbc
Stream #0:1[0x28a]: Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz,
stereo, s16p, 256 kb/s
Stream #0:2[0x240](eng): Subtitle: dvb_teletext ([6][0][0][0] / 0x0006)
Stream #0:3[0x157d]: Unknown: none ([11][0][0][0] / 0x000B)
Stream #0:4[0x157c]: Unknown: none ([5][0][0][0] / 0x0005)
At least one output file must be specified
$ mediainfo 1002_20180317093300.ts
General
ID : 593 (0x251)
Complete name : 1002_20180317093300.ts
Format : MPEG-TS
File size : 561 MiB
Duration : 27 min 2 s
Overall bit rate mode : Variable
Overall bit rate : 2 901 kb/s
Video
ID : 512 (0x200)
Menu ID : 1 (0x1)
Format : MPEG Video
Format version : Version 2
Format profile : Main@Main
Format settings : CustomMatrix / BVOP
Format settings, BVOP : Yes
Format settings, Matrix : Custom
Format settings, GOP : Variable
Format settings, picture structure : Frame
Codec ID : 2
Duration : 27 min 2 s
Bit rate mode : Variable
Bit rate : 2 499 kb/s
Maximum bit rate : 6 000 kb/s
Width : 720 pixels
Height : 576 pixels
Display aspect ratio : 16:9
Frame rate : 25.000 FPS
Standard : PAL
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Top Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.241
Stream size : 483 MiB (86%)
Writing library : xec 7.1.18
Color primaries : BT.601 PAL
Transfer characteristics : BT.470 System B, BT.470 System G
Matrix coefficients : BT.470 System B, BT.470 System G
Audio
ID : 650 (0x28A)
Menu ID : 1 (0x1)
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Codec ID : 3
Duration : 27 min 2 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Maximum bit rate : 272 kb/s
Channel(s) : 2 channels
Sampling rate : 48.0 kHz
Frame rate : 41.667 FPS (1152 SPF)
Compression mode : Lossy
Delay relative to video : -419 ms
Stream size : 49.5 MiB (9%)
Text
ID : 576 (0x240)-801
Menu ID : 1 (0x1)
Format : Teletext Subtitle
Language : English
Menu
ID : 256 (0x100)
Menu ID : 1 (0x1)
List : 512 (0x200) (MPEG Video) /
650 (0x28A) (MPEG Audio) / 576 (0x240)-801 (Teletext Subtitle, en)
Language : / / English
Maximum bit rate : 6726000
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