Uprezing to Prores HQ with M2t and Itunes Specs

[vinbel]

Hi everybody,

i've already posted a thread about uprezing to prores, but what finally worked pretty fine with a file, didn't work with another one.

Here's the deal.

source specs:
Video : 00:03:55,880, 25,000 ips interlaced, 1440x1080x12, MPEG-2
Audio : 00:03:55,880, 48*000 Hz; Stéréo, MPEG Layer 2

output specs:
video: Apple PRO RES 422HQ 1920x1080 ~220 Mb/s, 25 fps, YUV colorspace
audio: mp2, 48 kHz, 16 bits, 384 kb/s, 2 channels (stereo)

ffmbc -i input.m2t -vcodec prores -qscale 1 -r 25 -acodec mp2 -sample_fmt s16 -ar 48000 -ab 384k -ac 2 -vf scale=1920:1080 output.mov

I never get a bitrate up to 150 mb (minimum bitrateso the video is accpted by my uplaod system).

can anyone help me with this one.

I don't really understand what makes a video conversion go fine with one and bad with another.

Thanks in advance


Vincent

[poisondeathray]

The resultant bitrate is determined by the source content complexity. For example, if it was still image, the bitrate might be 50Mb/s . If there was lots of action and noise it might be 350Mb/s

You probably don't have enough real details or content complexity (motion, noise, details) in the source video - and have saturated the encoder

The solution is to add a bit of grain or noise

[vinbel]

I'll search the web anyway, but is there a better command to put noise in an image.

thanks in advance

Vincent

[poisondeathray]

Also, if that is an interlaced source (looks like "PAL" spec HDV ? ), you need to add "-tff" to the commandline

I don't know if ffmbc/ffmpeg has a noise generator offhand, but you can use some filters in avisynth

EDIT: looks like ffmpeg has an add noise filter
http://www.ffmpeg.org/ffmpeg-filters.html#noise

[Baldrick]

ffmpegx is not ffmbc. Moving you to our video conversion section.

[vinbel]

Well thank you poisondeathray I'm gonna check that;
The point is the video is Black and White that's perhaps the reason why i get a low bitrate

Thanks you a lot