QuickTime AMA should be using v210 for codecs that are 10 bit. Not all
codecs are and sometimes we aren't sure what QuickTime is actually doing
between our plug-in and the codec that is decompressing the image.
Michel
On 9/14/11 12:02 PM, "Michael Brockington" <brocking@sfu.ca> wrote:
>Hi Michel:
>
>Thanks for chiming in. So should AMA be getting all 10 bits into Avid
>from any 10-bit source, or does it vary with different quicktime codecs
>and different vendor plugins?
>
>Cheers,
>--Michael Brockington
>
>On 11-09-14 6:31 AM, Michel Rynderman wrote:
>> Using the traditional QuickTime import method, we let QuickTime perform
>>the conversion to 8 bit and I don't know what Apple does in their
>>conversion process. Using QuickTime AMA we generally get YUV data that¹s
>>either 10 bit already via a format called "v210". From there, if you
>>choose to transcode to an 8 bit format, we should be rounding the data
>>down from 10 to 8.
>>
>> Michel Rynderman
>> Avid
>>
>> From: Avid-L2@yahoogroups.com<mailto:Avid-L2@yahoogroups.com>
>>[mailto:Avid-L2@yahoogroups.com] On Behalf Of johnrobmoore
>> Sent: Tuesday, September 13, 2011 6:12 PM
>> To: Avid-L2@yahoogroups.com<mailto:Avid-L2@yahoogroups.com>
>> Subject: [Avid-L2] Re: 10bit workflows revisited...
>>
>>
>>
>> I found a discussion on rounding through google and here's what someone
>>said in the discussion but this was about going 10 bit to 8 bit in a
>>generic sense it wasn't about video but data in general so I don't know
>>if it's accurate but it made sense to me.:
>>
>> "If it was me I would read the 10 bits and use a rounding algorithm. If
>>the low two bits are 00 or 01 drop them and take the most significant 8
>>bits. If the low two bits are 10 or 11, then round up by adding 1 to the
>>most significant eight bits."
>>
>> Is there any other way to round? I did read about "double rounding"
>>where the value gets bumped twice on a desktop display but I didn't
>>follow how the double bump actually occurred. Sounds like a question for
>>SUPER CODEC MAN. Mr. Rynderman are you out there? Hollywood is losing 2
>>bits of data and I'm afraid we're being truncated. Could you explain how
>>Avid rounds 10 bit to 8 bit so tinsel town can rest easy tonight? ;-)
>>
>> --- In Avid-L2@yahoogroups.com<mailto:Avid-L2%40yahoogroups.com>,
>>"Terence Curren"<tcurren@...> wrote:
>>> Depends upon how well the rounding is handled. If not done correctly,
>>>you can get a slight shift to green when rounding from 10 to 8.
>>>
>>> --- In Avid-L2@yahoogroups.com<mailto:Avid-L2%40yahoogroups.com>,
>>>"johnrobmoore"<bigfish@> wrote:
>>>> I was told the avid doesn't truncate but rounds when you lose bits.
>>>>Not a big deal but my understanding is rounding is better than just
>>>>loping of the extra bits.
>>>>
>>>> --- In Avid-L2@yahoogroups.com<mailto:Avid-L2%40yahoogroups.com>,
>>>>Michael Brockington<brocking@> wrote:
>>>>> What was the codec for your original QT? If it was Avid 10-bit media,
>>>>> and you were able to fast-import it, then you're OK for the first
>>>>>step,
>>>>> otherwise it was probably truncated on import.
>>>>>
>>>>> Cheers,
>>>>> --Michael
>>>>>
>>>>> On 11-09-12 4:15 PM, ripvanmarlowe2000 wrote:
>>>>>> Had an interesting one today which required a bit of grey matter
>>>>>>and I
>>>>>> remember some discussion about this a while back and i think I've
>>>>>> managed to keep all my bits in place but does this sound right to
>>>>>>people?
>>>>>>
>>>>>> Client wants a 59.94 10bit uncompressed QT from a 25fps 1920x1080
>>>>>> 10bit uncompressed master QT.
>>>>>>
>>>>>> Starting with the uncompressed 10bit QT I imported into Avid as 1:1X
>>>>>> MXF. Played out to 50i HDCAM SR with 10bit checked in digicut tool.
>>>>>> Reconfigured the SR to play back the tape at 23.98 and format
>>>>>>convert
>>>>>> to 59.94 then captured the 59.94 footage back in to a new 59.94
>>>>>> project as 1:1x MXF then exported as Same as source QT.
>>>>>>
>>>>>> Have i kept all my 10 bits using this workflow? Man those SRW-5500s
>>>>>> are cool!
>>>>>>
>>>>>> Andi
>>>>>>
>>>>>>
>>>>>
>>>>> [Non-text portions of this message have been removed]
>>>>>
>>
>>
>> [Non-text portions of this message have been removed]
>>
>>
>>
>> ------------------------------------
>>
>> Search the offical complete Avid-L archives at:
>>http://archives.bengrosser.com/avid/
>>
>> If you want to donate to Red Cross quake relief, you can do so through
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>>
>>
>>
>>
If you want to donate to Red Cross quake relief, you can do so through your cell phone. Text redcross to 90999 to make a $10 donation. It will be on your next cell bill.
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