[FFmpeg-user] ffmpeg h.264 long gop encoding and interlaced encoding

[Filippo Righi]

Hi there,
i am trying to convert a MOV video into a MP4 (progressive).
I would like to maintain the same GOP settings codification.
This are metadata of my video:

    fil at fil-ubuntu:~/Scrivania$ mediainfo 720p_50p_full.MOV
    General
    Complete name : 720p_50p_full.MOV
    Format : MPEG-4
    Format profile : QuickTime
    Codec ID : qt
    File size : 81.3 MiB
    Duration : 8s 560ms
    Overall bit rate mode : Variable
    Overall bit rate : 79.7 Mbps
    Encoded date : UTC 2013-02-15 13:08:12
    Tagged date : UTC 2013-02-15 13:08:12
    Copyright : http://www.technophil.sm
    com.apple.quicktime.make : Canon
    com.apple.quicktime.model : Canon EOS 6D
    com.apple.quicktime.author : TechnoPhil

    Video
    ID : 1
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : High at L5.1
    Format settings, CABAC : No
    Format settings, ReFrames : 1 frame
    Format settings, GOP : N=1
    Codec ID : avc1
    Codec ID/Info : Advanced Video Coding
    Duration : 8s 560ms
    Bit rate mode : Variable
    Bit rate : 78.0 Mbps
    Width : 1 280 pixels
    Height : 720 pixels
    Display aspect ratio : 16:9
    Frame rate mode : Constant
    Frame rate : 50.000 fps
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Progressive
    Bits/(Pixel*Frame) : 1.693
    Stream size : 79.6 MiB (98%)
    Language : English
    Encoded date : UTC 2013-02-15 13:08:12
    Tagged date : UTC 2013-02-15 13:08:12
    Color primaries : BT.709
    Transfer characteristics : BT.709
    Matrix coefficients : BT.709


I am using this script:

for i in *.MOV; do newname=`basename $i .MOV`.mp4; ffmpeg -i $i -s 1280x720 -b 5000k -bt 10000k -aspect 16:9 -r 50 -vcodec libx264 -ac 2 -ar 48000 -ab 256k -threads 4 $newname; done

The result is:

    fil at fil-ubuntu:~/Scrivania$ mediainfo 720p_50p_full.mp4
    General
    Complete name : 720p_50p_full.mp4
    Format : MPEG-4
    Format profile : Base Media
    Codec ID : isom
    File size : 5.29 MiB
    Duration : 8s 576ms
    Overall bit rate : 5 170 Kbps
    Encoded date : UTC 2013-02-15 13:08:12
    Tagged date : UTC 2013-02-15 13:08:12
    Writing application : Lavf53.21.1

    Video
    ID : 1
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : Main at L3.2
    Format settings, CABAC : Yes
    Format settings, ReFrames : 3 frames
    Codec ID : avc1
    Codec ID/Info : Advanced Video Coding
    Duration : 8s 560ms
    Bit rate : 5 000 Kbps
    Width : 1 280 pixels
    Height : 720 pixels
    Display aspect ratio : 16:9
    Frame rate mode : Constant
    Frame rate : 50.000 fps
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Progressive
    Bits/(Pixel*Frame) : 0.109
    Stream size : 5.01 MiB (95%)
    Writing library : x264 core 123 r2189 35cf912
    Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=4 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=1 / weightb=0 / open_gop=1 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=5000 / ratetol=1.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.25 / aq=1:1.00
    Language : English
    Encoded date : UTC 2013-02-15 13:08:12
    Tagged date : UTC 2013-02-15 13:08:12

How can i maintain the same GOP settings codification for both progressive and interlaced video files?
And how can i change the "scan type" into interlaced?
How can i change the "scan order" (Bottom Field First - Top Field First) fot interlaced encoding?

    ...
    Complete name : 109G0135_01_1080i.MP4
    Format : MPEG-4
    Commercial name : XDCAM EX 35
    Format profile : Base Media / Version 2
    Codec ID : mp42
    File size : 59.2 MiB
    Duration : 13s 920ms
    Overall bit rate mode : Variable
    Overall bit rate : 35.7 Mbps
    Encoded date : UTC 2012-01-21 23:51:10
    Tagged date : UTC 2012-01-21 23:51:10

    Video
    ID : 1
    Format : MPEG Video
    Commercial name : XDCAM EX 35
    Format version : Version 2
    Format profile : Main at High
    Format settings, BVOP : Yes
    Format settings, Matrix : Custom
    Format settings, GOP : M=3, N=12
    Codec ID : 61
    Duration : 13s 920ms
    Bit rate mode : Variable
    Bit rate : 34.0 Mbps
    Maximum bit rate : 35.0 Mbps
    Width : 1 920 pixels
    Height : 1 080 pixels
    Display aspect ratio : 16:9
    Frame rate mode : Constant
    Frame rate : 25.000 fps
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Interlaced
    Scan order : Top Field First
    Compression mode : Lossy
    ...


Best regards.

Filippo