[Libav-user] MPEG2 Encoding with a determined bit_rate

francesco at bltitalia.com francesco at bltitalia.com
Tue Mar 13 11:12:15 CET 2012

At 11.02 13/03/2012 +0200, you wrote:
>2012/3/13  <francesco at bltitalia.com>:
>> Hi to all
>> I am attempting to convert in mpeg2 with a bitrate of 30Mbit/sec and with a
>> 50Mbit/sec but it seems that the bit rate  variation doesn't work.
>> Here is my routine that gets as input a buffer with my originary coded frame
>> (not interlaced),
>> decompress and interlace it and recompress using MPEG2 compressor (Hsize and
>> VSize are field dimension,this is why the VSize is doubled):
>Please provide minimal, but compiling source code of your app that
>reproduces the issue.
>Besides that, i recommend you to check that you feed in frames with
>timestamps in encoder's AVCodecContext.time_base.
>Printing pts of frames/packets you produce can help in debugging it.
>Andrey Utkin
>Libav-user mailing list
>Libav-user at ffmpeg.org
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Hi Andrey
I can't provide compiling code because this routine is part of a complex
program.  Mainly I start from a Jpeg200 compressed frame (divided in two
separately compressed fields), I decompress the two fields, interlace them
and give it to the avcodec library for compressing in MPEG2. So I compress 1
frame at a time. Each frame is a I-Mode frame. 
I don't touch the AVCodecContext.time_base.  Should I ?
best regards

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