h264 smart render problem

18th Aug 2010 14:13 #1

Member

Hi.

I have big.mp4 file (h264 video stream). I want to cut out a part from it, but without the full recoding, instead recoding only necessary small part.

So I've copied (without recode) a part of big.mp4 to ffmpeg_copied.mp4, using ffmpeg tool :

Code:

ffmpeg -i big.mp4 -y -ss 0 -t 3 -vcodec copy -an ffmpeg_copied.mp4

And recoded another part to ffmpeg_recoded.mp4, using ffmpeg tool :

Code:

ffmpeg -i big.mp4 -y -ss 29 -t 3 -vcodec libx264  -vpre hq -vpre main -b 1200k -coder 0 -refs 6 -an ffmpeg_recoded.mp4

But when I join ffmpeg_copied.mp4 and ffmpeg_recoded.mp4, using mp4box tool :

Code:

mp4box ffmpeg_copied.mp4 -cat ffmpeg_recoded.mp4 -out copied_recoded.mp4

I get

Code:

Appending file ffmpeg_recoded.mp4. 
No suitable destination track found - creating new one (type vide)

error.
And the resulting file contains the two joining files in different streams. So, the player plays only the first.

When doing the recode I've chosen the settings to meet the original file's (big.mp4) properties. I've looked this properties using MediaInfo tool. The properties are shown at the end of the post.

(Joining of two different recoded files or two different copied files goes with no problem.)

I guess the problem is that I don't see some properties of big.mp4, so I couldn't meet 'em in my encoding settings.
MediaInfo tool shows only CABAC and ReFrames properties, but no bframes or dct8x8 e.g.

Could you advise me a way to get all the characteristics of big.mp4, so I would be able to specify 'em in my encoding settings.

If my guess is wrong, please give me a clue to the source of the problem.

--------------
The files:
are in the attachment.

--------------
The properties of files:

Code:

big.mp4
        General
        Complete name                    : F:\Utility\u\TPr\mp4Box\forPost\big.mp4
        Format                           : MPEG-4
        Format profile                   : Base Media
        Codec ID                         : isom
        File size                        : 3.76 MiB
        Duration                         : 40s 0ms
        Overall bit rate                 : 789 Kbps
        Encoded date                     : UTC 2010-08-17 18:01:07
        Tagged date                      : UTC 2010-08-17 18:01:07

        Video
        ID                               : 1
        Format                           : AVC
        Format/Info                      : Advanced Video Codec
        Format profile                   : High@L5.1
        Format settings, CABAC           : No
        Format settings, ReFrames        : 6 frames
        Codec ID                         : avc1
        Codec ID/Info                    : Advanced Video Coding
        Duration                         : 40s 0ms
        Bit rate mode                    : Variable
        Bit rate                         : 815 Kbps
        Maximum bit rate                 : 1 307 Kbps
        Width                            : 480 pixels
        Height                           : 360 pixels
        Display aspect ratio             : 4:3
        Frame rate mode                  : Constant
        Frame rate                       : 25.000 fps
        Resolution                       : 24 bits
        Colorimetry                      : 4:2:0
        Scan type                        : Progressive
        Bits/(Pixel*Frame)               : 0.189
        Stream size                      : 3.76 MiB (100%)
        Encoded date                     : UTC 2010-08-17 17:59:10
        Tagged date                      : UTC 2010-08-17 18:01:08

Code:

ffmpeg_recoded.mp4
        General
        Complete name                    : F:\Utility\u\TPr\mp4Box\forPost\ffmpeg_recoded.mp4
        Format                           : MPEG-4
        Format profile                   : Base Media
        Codec ID                         : isom
        File size                        : 334 KiB
        Duration                         : 3s 0ms
        Overall bit rate                 : 912 Kbps
        Writing application              : Lavf52.78.0

        Video
        ID                               : 1
        Format                           : AVC
        Format/Info                      : Advanced Video Codec
        Format profile                   : Main@L2.1
        Format settings, CABAC           : No
        Format settings, ReFrames        : 6 frames
        Codec ID                         : avc1
        Codec ID/Info                    : Advanced Video Coding
        Duration                         : 3s 0ms
        Bit rate mode                    : Variable
        Bit rate                         : 907 Kbps
        Nominal bit rate                 : 1 200 Kbps
        Width                            : 480 pixels
        Height                           : 360 pixels
        Display aspect ratio             : 4:3
        Frame rate mode                  : Constant
        Frame rate                       : 25.000 fps
        Resolution                       : 24 bits
        Colorimetry                      : 4:2:0
        Scan type                        : Progressive
        Bits/(Pixel*Frame)               : 0.210
        Stream size                      : 332 KiB (99%)
        Writing library                  : x264 core 98 r1629 9d1c441
        Encoding settings                : cabac=0 / ref=6 / deblock=1:0:0 / analyse=0x1:0x111 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / constrained_intra=0 / bframes=3 / b_pyramid=0 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=1200 / ratetol=3.3 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.41 / aq=1:1.00