[FFmpeg-devel] [PATCH] lavc/dnxhddata: fix bitrates for cid 1251 and 1252 in cid table

[Matthieu Bouron]

On Tue, Jan 22, 2013 at 2:18 PM, Tim Nicholson <nichot20 at yahoo.com> wrote:
> On 21/01/13 20:14, Matthieu Bouron wrote:
>> ---
>>
>> Hi there,
>>
>> According to SMPTE S2019-1, bitrates should be:
>>   - 180Mbps for cid 1251 at 50fps,
>>   - 120Mbps for cid 1252 at 50fps.
>
> Looking at Annex F in my SMPTE S2019-1-2008 suggests 25fps figures are
> wrong too..
>
> cid 1251 is { 90, 80, 180, 220 }
> cid 1252 is { 60, 60, 120, 145 }
>

The 75Mbps value "may" refer to the 29.97fps profile (which is
declared here: http://www.avid.com/static/resources/FR/documents/dnxhd.pdf
but not in the S2019). The single 60Mbps value refers here to the
23.976fps and 25fps profiles (this is how i understand it).

I have an upcoming patch which associate bitrate and framerate values
(in order to print valid dnxhd profiles if the codec parameters are
wrong).

Regards,
Matthieu

> Rounded to the nearest 5Mbps....
>
>>
>> Regards,
>> Matthieu
>>
>> ---
>>  libavcodec/dnxhddata.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavcodec/dnxhddata.c b/libavcodec/dnxhddata.c
>> index c433d9d..c9d82c8 100644
>> --- a/libavcodec/dnxhddata.c
>> +++ b/libavcodec/dnxhddata.c
>> @@ -1001,14 +1001,14 @@ const CIDEntry ff_dnxhd_cid_table[] = {
>>        dnxhd_1251_ac_codes, dnxhd_1251_ac_bits, dnxhd_1251_ac_level,
>>        dnxhd_1251_ac_flags,
>>        dnxhd_1251_run_codes, dnxhd_1251_run_bits, dnxhd_1251_run,
>> -      { 90, 110, 175, 220 } },
>> +      { 90, 110, 180, 220 } },
>>      { 1252, 1280,  720, 0, 303104, 303104, 4, 8, 5,
>>        dnxhd_1252_luma_weight, dnxhd_1252_chroma_weight,
>>        dnxhd_1252_dc_codes, dnxhd_1252_dc_bits,
>>        dnxhd_1252_ac_codes, dnxhd_1252_ac_bits, dnxhd_1252_ac_level,
>>        dnxhd_1252_ac_flags,
>>        dnxhd_1251_run_codes, dnxhd_1251_run_bits, dnxhd_1251_run,
>> -      { 60, 75, 115, 145 } },
>> +      { 60, 75, 120, 145 } },
>>      { 1253, 1920, 1080, 0, 188416, 188416, 4, 8, 3,
>>        dnxhd_1237_luma_weight, dnxhd_1237_chroma_weight,
>>        dnxhd_1237_dc_codes, dnxhd_1237_dc_bits,
>>
>
>
> --
> Tim
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