[FFmpeg-devel] [PATCH] H.264 fix interlacedflag:bringback pic_struct

[Haruhiko Yamagata]

>On Thu, May 28, 2009 at 11:23:17PM +0900, Haruhiko Yamagata wrote:
>>> On Thu, May 28, 2009 at 10:59:09PM +0900, Haruhiko Yamagata wrote:
>>>>> On Thu, May 28, 2009 at 09:24:59PM +0900, Haruhiko Yamagata wrote:
>>>>>> On Tue, Mar 03, 2009, Michael Niedermayer wrote:
>>>>>>> ct_type should always be used if available, otherwise
>>>>>>> FIELD_OR_MBAFF_PICTURE should be.
>>>>>>> that at least is how i understand the spec, if this fails for some
>>>>>>> case iam interrested in the file
>>>>>>
>>>>>> Excuse me for late response, I found a file which fails.
>>>>>> http://x264.nl/h.264.samples/premiere-paff.ts
>>>>>>
>>>>>> Please note that ct_type is optional in the picture timing SEI.
>>>>>>
>>>>>>>            if(get_bits(&s->gb, 1)){                  /* 
>>>>>>> clock_timestamp_flag */
>>>>>>>                unsigned int full_timestamp_flag;
>>>>>>>                h->sei_ct_type |= 1<<get_bits(&s->gb, 2);
>>>>>>
>>>>>> That file does not have ct_type at all, but has correct pic_struct.
>>>>>> pic_struct is basically correct, only a few streams are badly encoded.
>>>>>> The attached patch fixes this issue and still honor ct_type if 
>>>>>> available.
>>>>>>
>>>>>> Best regards,
>>>>>> Haruhiko Yamagata
>>>>>
>>>>>>  h264.c |   19 +++++++++++++------
>>>>>>  1 file changed, 13 insertions(+), 6 deletions(-)
>>>>>> 832b6de132e2ccb691445f47a3ee3b56d0b1e65d  
>>>>>> check_presence_of_cy_type.patch
>>>>>> Index: libavcodec/h264.c
>>>>>> ===================================================================
>>>>>> --- libavcodec/h264.c (revision 18971)
>>>>>> +++ libavcodec/h264.c (working copy)
>>>>>> @@ -6866,7 +6866,7 @@
>>>>>>          for (i = 0 ; i < num_clock_ts ; i++){
>>>>>>              if(get_bits(&s->gb, 1)){                  /* 
>>>>>> clock_timestamp_flag */
>>>>>>                  unsigned int full_timestamp_flag;
>>>>>> -                h->sei_ct_type |= 1<<get_bits(&s->gb, 2);
>>>>>> +                h->sei_ct_type |= 1<<(get_bits(&s->gb, 2)+1);
>>>>>>                  skip_bits(&s->gb, 1);                 /* 
>>>>>> nuit_field_based_flag */
>>>>>>                  skip_bits(&s->gb, 5);                 /* counting_type 
>>>>>> */
>>>>>
>>>>> why?
>>>>
>>>> So that h->sei_ct_type will be none zero if ct_type exists, even if 
>>>> ct_type is zero.
>>>> In other words, h->sei_ct_type shall be zero if ct_type does not exit.
>>>
>>> so 1<<0 is 0 for you?
>>
>> My mistake.
>> A new patch attached.
>[...]
>> @@ -7819,6 +7823,9 @@
>>                  cur->interlaced_frame = FIELD_OR_MBAFF_PICTURE;
>>              }
>>  
>> +            if (h->sei_ct_type)
>> +                cur->interlaced_frame = (h->sei_ct_type & (1<<1)) != 0;
>
>this overrides the value set from SEI_PIC_STRUCT_FRAME_TRIPLING:

Yes, I moved the two lines into if(h->sps.pic_struct_present_flag) block and
added check.

Best regards,
Haruhiko Yamagata
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