[FFmpeg-user] vertical lines noise in scaled raw video.

[Dennis]

>
> On Wed, Nov 9, 2011 at 11:05 AM, Andy Sheen <sheen.andy at googlemail.com>wrote:
>
>> I've downloaded your ffmpeg recode. As far as I can tell I can't see any
>> vertical lines on a calibrated monitor (playing with mpc-hc).
>>
>> Do you have the latest drivers for your graphics card? Tried it on a
>> different PC/output device? It may be a rendering problem.
>>
>> Dennis wrote on Wed 09 Nov at 15:31 UK time
>> > A long story, but will try to keep it short.
>> >
>> > Was converting MPEG2 to H,.264 noticed that video has faint but
>> persistent
>> > vertical lines top to bottom. It's not extremely noticeable, but gets
>> very
>> > annoying as lines stay in one place and 'burn in' after a while.
>> >
>> > Playback: QuickTime, VLC and FFplay media players.
>> > Encoding: FFmpeg 0.8.6 release with latest libx264 (Nov 5th tar ball).
>> >
>> > Source file:http://www.mediafire.com/?khrzaps202b1ksq
>> > FFmpeg & libx264: http://www.mediafire.com/?3fkyzo1oh5d6l72
>> > X264 encode(y4m to H264): http://www.mediafire.com/?g8x2ww1rcwhm08k
>> > y4m file (scaled to 800x448 by ffmpeg):
>> > http://www.mediafire.com/?y8cvvk07r1vegna
>> >
>> > Any advice on removing these lines, perhaps a video filter? Or other
>> ways
>> > control the reduction of chroma spread, so that dark grays are encoded
>> as
>> > black?
>>
>
> Here's the screenshot of the scaled y4m with "find edges" filter applied
> by ImageJ : http://www.mediafire.com/?0hesdf21e6a2ok2
> these  lines get amplified when encoded by x264, if I can suppress the
> amplification it'd be kinda cool.
>
> Versus unscaled y4m screenshot with the same filter applied - its just
> solid black: http://www.mediafire.com/?5m3seip1z8zb4mf
>