Frame rate problem

[Serenato]

Hello!

I've been encoding a 1280x720 video without resizing, but joining it to another video and added 2 subtitles (one is a logo, the another is the op-ed karaoke). There are some parts where I can exactly tell if the quality got lower or higher. So I choosed x264 2pass Anime_Toons HQ (since my video is an anime) with the following settings: bitrate: 1951, deblocking 1;1, b-frames 16. The other settings still on the default. The encoding went well, but on a certain part, I can see that the picture gotten worse. I tried to test it more, so I cut those scenes to see whether the settings are wrong or not. The result: the video was perfect, even with the joined part and subtitles. Still, if I encode the whole video, the mess come back again. And some odd things occured meanwhile: the frame rate of the encoded video is not the original 23,976 fps, but 202 fps. How? Here are the properties of the four videos:

Original:

Overall bit rate : 2 930 Kbps

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L5.0
Format settings, CABAC : Yes
Format settings, ReFrames : 11 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 23mn 54s
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Title : [H264]
Writing library : x264 core 115 r1995 c1e60b9

Join-video

Overall bit rate : 2 024 Kbps

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.1
Format settings, CABAC : Yes
Format settings, ReFrames : 3 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Bit rate mode : Variable
Bit rate : 1 951 Kbps
Maximum bit rate : 6 108 Kbps
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.088
Stream size : 6.39 MiB (100%)
Writing library : x264 core 120 r2120 0c7dab9

Cutted scenes

Overall bit rate : 1 906 Kbps

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.0
Format settings, CABAC : Yes
Format settings, ReFrames : 8 frames
Format settings, GOP : M=6, N=20
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1mn 37s
Bit rate mode : Variable
Bit rate : 1 951 Kbps
Maximum bit rate : 13.3 Mbps
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.088
Stream size : 22.2 MiB (100%)
Writing library : x264 core 119 r2106 07efeb4



Encoded video

Overall bit rate : 2 149 Kbps

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.0
Format settings, CABAC : Yes
Format settings, ReFrames : 8 frames
Format settings, GOP : M=1, N=21
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 24mn 21s
Bit rate mode : Variable
Bit rate : 1 951 Kbps
Maximum bit rate : 58.4 Mbps
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 202 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.088
Stream size : 340 MiB (91%)
Writing library : x264 core 119 r2106 07efeb4



Could you help me, please?

[poisondeathray]

Post your avs script, and your logfile for the encode

If you type info() at the bottom of the script and preview it, what does it say about the fps ?

[Serenato]

I'm still away from my computer, but I know my script look like this:


v1=DirectShowSource("D:\source.mkv",audio=false)
v2=DirectShowSource("D:\extra.mp4",audio=false)
v1 + v2
TextSub("D:\logo.ass")
TextSub("D:\Op-Ed 01.ass")
ConvertToYV12()


For example, if I use Format Factory to watch the encoded video's properties, it says 23,976 fps, but if I right click on the video to see its properties, it says 202 fps. Of course, I don't believe in Windows at all, but how come this difference in the cutted and the whole video if the settings are the same?

[poisondeathray]

Maybe mediainfo is incorrect in reporting ? The method you used in "cutting" that encoded section for examination may have caused the issue (e.g. not cutting on keyframes)



For the script, Avisynth won't let you append v1+v2 if the frame rates differ between source.mkv and extra.mp4 anyway

Info() will report the FPS, and encode log file will provide the other information regarding the encode

So assuming those were correct, the issue was probably with cutting the segment - provide more information on how you did this

[Serenato]

i run it with AvsPmod and first, it really complaines about the different frame rate, so I converted that extra video from 29 fsp to 23,976 fps. And after changing the video to this new one, the script run with no problem. As I said, if I cut and join several scenes from the whole video (including the extra one), the result is perfect. But when I converted the whole video with the same setting, the quality dropped, especially in certain scenes. Players read it well, but why the quality dropped?

[poisondeathray]

If you're concerned about the quality drop, use a higher bitrate


Original:
Overall bit rate : 2 930 Kbps



Encoded video
Overall bit rate : 2 149 Kbps


You need HIGHER than original , to get lower quality. It will never be the same quality, it will only drop when you use lossy encoding. At minimum you should use similar bitrates