notes:random
This is an old revision of the document!
Table of Contents
Random Notes
Out-of-place stuffs…
Video Notes
| NTSC |
- used mainly in US, Japan
- 60 Hz, 525 lines at 30 fps (480i)
- resolution ⇒ 720 x 480 (DVD-NTSC?)
| PAL |
- used mainly in UK, Europe, SE Asia
- 50 Hz, 625 lines at 25 fps (576i)
- resolution ⇒ 720 x 576 (DVD-PAL?)
| Standard | Supported Aspect Ratio |
|---|---|
| MPEG | 1:1 4:3 2.11:1 16:9 |
| TV | 4:3 16:9 |
| Settings | Resolution |
|---|---|
| Fullscreen (Std) | 4:3 |
| Widescreen | 16:9 (LetterBox) |
| Widescreen | 16:9 (Anamorphic) |
Issue Running ImageMagick's Convert
I got the following error message
convert-im6.q16: attempt to perform an operation not allowed by the security policy `EPS'
I got the solution from here. It turns out, there is a security feature that we need to grant. Edit file /etc/ImageMagick-6/policy.xml. Find the following line,
<policy domain="coder" rights="none" pattern="EPS" />
and change the rights value to read|write.
Live Video Streaming using ffmpeg
Dumping this here as it is for now…
# may run on ramdisk? - hls? ffmpeg -f v4l2 -i /dev/video0 -strict experimental -pix_fmt yuv420p playlist.m3u8 - generic segmenter? ffmpeg -f v4l2 -framerate 25 -video_size 640x480 -i /dev/video0 -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4 - option to place keyframe every 2s (every 50 frames at 25fps) -c:v libx264 -r 25 -g 50 *note: segment_time should be multiple of keyframe interval We need to modify /etc/apache2/mods-available/mime.conf AddType application/x-mpegURL .m3u8 AddType video/MP2T .ts
Analysis of Android (cheap, china made) disk parition layout
Dumped…
https://spflashtool.com/download/ SP_Flash_Tool-5.1916_Linux.zip => ./adb shell $ cat /proc/mtd dev: size erasesize name $ cat /proc/dumchar_info Part_Name Size StartAddr Type MapTo preloader 0x0000000000880000 0x0000000000000000 2 /dev/misc-sd mbr 0x0000000000080000 0x0000000000000000 2 /dev/block/mmcblk0 ebr1 0x0000000000080000 0x0000000000080000 2 /dev/block/mmcblk0p1 pro_info 0x0000000000300000 0x0000000000100000 2 /dev/block/mmcblk0 nvram 0x0000000000500000 0x0000000000400000 2 /dev/block/mmcblk0 protect_f 0x0000000000a00000 0x0000000000900000 2 /dev/block/mmcblk0p2 protect_s 0x0000000000a00000 0x0000000001300000 2 /dev/block/mmcblk0p3 seccfg 0x0000000000020000 0x0000000001d00000 2 /dev/block/mmcblk0 uboot 0x0000000000060000 0x0000000001d20000 2 /dev/block/mmcblk0 bootimg 0x0000000000600000 0x0000000001d80000 2 /dev/block/mmcblk0 recovery 0x0000000000600000 0x0000000002380000 2 /dev/block/mmcblk0 sec_ro 0x0000000000040000 0x0000000002980000 2 /dev/block/mmcblk0 misc 0x0000000000080000 0x00000000029c0000 2 /dev/block/mmcblk0 logo 0x0000000000300000 0x0000000002a40000 2 /dev/block/mmcblk0 expdb 0x0000000000a00000 0x0000000002d40000 2 /dev/block/mmcblk0 android 0x0000000035200000 0x0000000003740000 2 /dev/block/mmcblk0p4 cache 0x000000000e200000 0x0000000038940000 2 /dev/block/mmcblk0p5 usrdata 0x000000009e360000 0x0000000046b40000 2 /dev/block/mmcblk0p6 bmtpool 0x0000000001500000 0x00000000ff7700a8 2 /dev/block/mmcblk0 Part_Name:Partition name you should open; Size:size of partition StartAddr:Start Address of partition; Type:Type of partition(MTD=1,EMMC=2) MapTo:actual device you operate $ getprop ro.build.ab_update - returns nothing... so, using A-only partition scheme (instead of newer A-B scheme)
notes/random.1775354645.txt.gz · Last modified: by azman