[Ffmpeg-devel] [RFC] D10 IMX patch encoding

Baptiste Coudurier baptiste.coudurier
Sat Mar 3 14:48:48 CET 2007


Hi

Michael Niedermayer wrote:
> Hi
> 
> On Wed, Jan 24, 2007 at 05:42:50PM +0100, Baptiste Coudurier wrote:
>> Hi
>>
>> This patch add features to be able to encode D10 streams (SMPTE 356M,
>> also known as IMX)
>>
>> Current rc code cannot support non linear quant, therefore, I workaround
>> mpeg2 quantizer to be able to put 1 as q_scale_type in bitstream,
>> meaning that qmax > 4 is not supported (yes, that's stupid but
>> q_scale_type 0 is forbidden in D10, and bitrate is either 30/40/50 Mb/s)
> 
> i dont like the qmax > 4 limit, and the qscale encoding has nothing to do
> with the RC code, snow uses a logarithmic qscale and that works too

I followed your instructions, qmax > 12 now, and use a inv table.

>> Add support for one mb per slice.
> 
> setting the rtp packet size (or whatever the field in AVCodecContext was 
> called) to 1 should have that effect too with no other code changes 

Indeed.

>> Add IMX bitstream filter to mux D10 stream into mov, and workaround to
>> set acceptable width/height by Final Cut, only PAL was tested. (coded
>> height is 608, while display height must be 576)

I split patch in 3, see attached.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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