[FFmpeg-user] IMX50 NTSC framesize differs to the SMPTE 356M-2001 Standard - why?

tim nicholson nichot20 at yahoo.com
Tue Jun 16 12:06:58 CEST 2015


On 16/06/15 09:33, Christoph Gerstbauer wrote:
> 
>>> 1.) Please can you tell me YOUR used syntaxes for IMX30/40/50  for PAL
>>> and NTSC? I want to compare it to mine.
>> Mine look remarkably similar to yours except for the ommission of 'ilme'
>> which makes no sense for an I frame only format.
>>
>> I don't think I've ever  used 40M, we either use 50 or 30 but my
>> buffers/init_occupancy are 1200000 PAL and 1001000 NTSC at 30M
> Hello Tim,
> 
> for IMX30 PAL/NTSC I have the same values like you.
> 
> whats your buffers/init_occupancy for IMX50 NTSC?
> 

Not sure I've ever had to do it, but a colleague uses an exact 50000000
bit rate which gives a 1668334 buffer and frame size of 208541 if all
figures are rounded to integers.

These files have generally been accepted the other side of the Atlantic.
As I've said before, the coder has got to reconcile a conflicting set of
integer values when dealing with NTSC frame rates. It would be
itneresting to diff frames made using the values above to those made
using your values derived by working back from the exact integer frame
size instead of forward from the bit rate.

> [...]
-- 
Tim.
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