1 2 Previous Next 16 Replies Latest reply: Dec 2, 2012 11:15 PM by shrnh
shrnh Level 1 Level 1 (0 points)

Hi,

 

I am trying to transcode a SD clip via compressor. Here's the settings that I would like to achieve.

 

Video Frame Rate

25 fps

Video Standard

PAL

Video Codec

MPEG-2 Video, Main Profile/Main Level

Audio Codec

MPEG-2 Audio Layer II or

Available audio codec

Container Format

Mpeg-2 Transport Stream  (mpg)

Video bit rate

8,000 Kbps, CBR

Audio Bit rate

384 Kbps

Aspect Ratio

16:9

Audio Sample Rate

48KHz

Resolution

1024x576

Scan type

Progressive

 

However, the only problem I have is transcoding the clip to CBR mode. Even though I have chosen the 'one-pass CBR mode' in Compressor, the output is still VBR mode. Is there any way for Compressor to follow the settings and achieve the CBR mode? Thanks in advance.


Mac OS X (10.6.8)
  • 1. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    I don't experience ythat. Where is it being reported as VBR? When I do a test clip and bring it into Media INFO, it reports as CBR. Same in MPEG Streamclip.

     

    Russ

  • 2. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    shrnh Level 1 Level 1 (0 points)

    Hi Russ,

     

    Thanks for your reply. I am using Compressor 3.5.3, not sure if this affects the result (as below and underlined for areas that are not achievable. I wish I could e-mail you the droplet.

     

    • Format                                   : MPEG-TS
    • File size                                : 31.3 MiB
    • Duration                                 : 30s 176ms
    • Overall bit rate mode                : Variable
    • Overall bit rate                         : 8 705 Kbps

     

     

    • Video ID                                  : 4096 (0x1000)
    • Menu ID                                  : 1 (0x1)
    • Format                                    : MPEG Video
    • Format version                         : Version 2
    • Format profile                           : Main@Main
    • Format settings, BVOP             : Yes
    • Format settings, Matrix              : Custom
    • Format settings, GOP                : M=3, N=12
    • Codec ID                                   : 2
    • Duration                                    : 30s 0ms
    • Bit rate                                     : 7 887 Kbps
    • Maximum bit rate                       : 8 000 Kbps
    • Width                                        : 720 pixels
    • Height                                       : 576 pixels
    • Display aspect ratio                    : 16:9
    • Frame rate                                 : 25.000 fps
    • Standard                                    : PAL
    • Color space                                : YUV
    • Chroma subsampling                   : 4:2:0
    • Bit depth                                    : 8 bits
    • Scan type                                   : Progressive
    • Compression mode                     : Lossy
    • Bits/(Pixel*Frame)                      : 0.761
    • Stream size                               : 28.2 MiB (90%)
    • Color primaries                          : BT.601 PAL
    • Transfer characteristics              : BT.470 System B, BT.470 System G
    • Matrix coefficients                      : BT.601

     

     

    • Audio
    • ID                                           : 4098 (0x1002)
    • Menu ID                                    : 1 (0x1)
    • Format                                     : MPEG Audio
    • Format version                          : Version 1
    • Format profile                             : Layer 2
    • Codec ID                                   : 3
    • Duration                                    : 30s 0ms
    • Bit rate mode                            : Constant
    • Bit rate                                      : 384 Kbps
    • Channel(s)                                 : 2 channels
    • Sampling rate                            : 48.0 KHz
    • Compression mode                    : Lossy
    • Stream size                              : 1.37 MiB (4%)

     

     

    • Menu
    • ID                                             : 110 (0x6E)
    • Menu ID                                  : 1 (0x1)
    • List                                           : 4096 (0x1000) (MPEG Video) / 4098 (0x1002) (MPEG Audio)
    • Maximum bit rate                      : 8797600
  • 3. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    No. I just tried C3.5 and was able to get a PAL sized CBR.

     

    Try a new job and not the droplet. in the Inspector>Encoder>Video Format, set to PAL.

     

    What app are you using to get the reported A/V info in your preceding post?

     

    Russ

  • 4. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    shrnh Level 1 Level 1 (0 points)

    Hi Russ, I've change a new job and tried again. It is still the same.

    I used Media Info.

  • 5. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    Could you post screen shots of your latest attempt? of the batch window…in the Inspector, the settings in Summary and Encoding panes?

     

    Russ

  • 6. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    ANd if I don't post any more tonight it's because I have the mother of all colds and am going to bed shortly.

  • 7. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    shrnh Level 1 Level 1 (0 points)

    Hi Russ,

     

    Here's the images.

    compressorimage1.jpg

     

    compressorimage2.jpg

  • 8. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    shrnh Level 1 Level 1 (0 points)

    compressorimage3.jpgcompressorimage4.jpgcompressorimage5.jpg

     

    Take care and rest well!

  • 9. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    The only thing I notice is your extension, which should be m2t.

     

    You started with the Transport STream preset, correct?

     

    Russ

  • 10. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    Just to add…what was your original footage – format and camera?

     

    I don't have any SD native progressive footage to test, although I can shoot some later today.

     

    Russ

  • 11. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    shrnh Level 1 Level 1 (0 points)

    Hi Russ,

     

    Hope u are feeling much better. Yes I did. I changed the name extension to mpg.

     

    The original footage is 1920x1080p, Apple ProRes 422. Hope this helps.

  • 12. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    Take your 1080p file and re-size it to a SD Pro Res file. Then take that file into a new job and do your MTS encode. You should be able to get a CBR from the SD source file.

     

    Russ

  • 13. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    Russ H Level 6 Level 6 (14,225 points)

    Just wondering whether you had any luck in getting CBR if you took my suggestion and first down-scaled your 1080p file to standard definition Pro Res and then encoded that SD file to MPEG.

     

    Russ

  • 14. Re: Variable bit rate (VBR) output with constant bit rate (CBR) settings?
    shrnh Level 1 Level 1 (0 points)

    Hi Russ,

     

    I have tried to export to SD ProRes and then transcode to mpg in Compressor. However, it still comes out the same (VBR mode).

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