[FFmpeg-devel] [PATCH]H.264fixinterlacedflag:bringback pic_struct
Michael Niedermayer
michaelni
Wed Jun 3 21:27:26 CEST 2009
On Wed, Jun 03, 2009 at 06:58:02PM +0900, Haruhiko Yamagata wrote:
>> On Tue, Jun 02, 2009 at 08:59:10PM +0900, Haruhiko Yamagata wrote:
>>>> On Sun, May 31, 2009 at 05:42:37PM +0900, Haruhiko Yamagata wrote:
>>>>>> On Fri, May 29, 2009 at 07:18:22PM +0900, Haruhiko Yamagata wrote:
>>>>>>>> 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
>>>>>>
>>>>>>> h264.c | 17 ++++++++++++-----
>>>>>>> 1 file changed, 12 insertions(+), 5 deletions(-)
>>>>>>> 3d86c0ddddd340d6af20ef493f043900ed02cc43
>>>>>>> check_presence_of_ct_type_3.patch
>>>>>>> Index: libavcodec/h264.c
>>>>>>> ===================================================================
>>>>>>> --- libavcodec/h264.c (revision 18980)
>>>>>>> +++ libavcodec/h264.c (working copy)
>>>>>>> @@ -7790,14 +7790,18 @@
>>>>>>> /* Signal interlacing information externally. */
>>>>>>> /* Prioritize picture timing SEI information over used
>>>>>>> decoding process if it exists. */
>>>>>>> - if (h->sei_ct_type)
>>>>>>> - cur->interlaced_frame = (h->sei_ct_type & (1<<1)) !=
>>>>>>> 0;
>>>>>>> - else
>>>>>>> - cur->interlaced_frame = FIELD_OR_MBAFF_PICTURE;
>>>>>>> -
>>>>>>> if(h->sps.pic_struct_present_flag){
>>>>>>> switch (h->sei_pic_struct)
>>>>>>> {
>>>>>>> + case SEI_PIC_STRUCT_FRAME:
>>>>>>> + cur->interlaced_frame = 0;
>>>>>>> + break;
>>>>>>> + case SEI_PIC_STRUCT_TOP_FIELD:
>>>>>>> + case SEI_PIC_STRUCT_BOTTOM_FIELD:
>>>>>>> + case SEI_PIC_STRUCT_TOP_BOTTOM:
>>>>>>> + case SEI_PIC_STRUCT_BOTTOM_TOP:
>>>>>>> + cur->interlaced_frame = 1;
>>>>>>> + break;
>>>>>>> case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
>>>>>>> case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
>>>>>>> // Signal the possibility of telecined film
>>>>>>> externally (pic_struct 5,6)
>>>>>>> @@ -7814,6 +7818,9 @@
>>>>>>> cur->repeat_pict = 4;
>>>>>>> break;
>>>>>>> }
>>>>>>> +
>>>>>>> + if (h->sei_ct_type && h->sei_pic_struct <=
>>>>>>> SEI_PIC_STRUCT_BOTTOM_TOP)
>>>>>>> + cur->interlaced_frame = (h->sei_ct_type &
>>>>>>> (1<<1)) != 0;
>>>>>>
>>>>>> i think that leaves at least one case where interlaced_frame frame is
>>>>>> not
>>>>>> initialized
>>>>>>
>>>>>>
>>>>>>> }else{
>>>>>>> /* Derive interlacing flag from used decoding
>>>>>>> process. */
>>>>>>> cur->interlaced_frame = FIELD_OR_MBAFF_PICTURE;
>>>>>
>>>>> In this case, neither pic_struct nor ct_type is available.
>>>>> This is the best information that we can have here.
>>>>> Both pic_struct and ct_type are under pic_struct_present_flag.
>>>>
>>>> ct_type is under clock_timestamp_flag, pic_struct is not
>>>> also ct_type can be set to "unknown" the code should fallback to
>>>> someting
>>>> else in that case
>>>
>>> The spec says
>>>> If CpbDpbDelaysPresentFlag is equal to 1 or pic_struct_present_flag is
>>>> equal to 1,
>>>> one picture timing SEI message shall be present in every access unit of
>>>> the coded
>>>> video sequence.
>>>
>>> So if pic_struct_present_flag is equal to 1, decode_picture_timing shall
>>> be called
>>> and h->sei_ct_type shall be flagged unknown (0) or set correct value.
>>
>> 0 is not the only value that means unknown
>>
>>
>>>
>>> In my patch,
>>>
>>>> + if (h->sei_ct_type && h->sei_pic_struct <=
>>>
>>> Presence of ct_type is checked here. This is only referenced if
>>> pic_struct_present_flag is equal to 1.
>>
>> and if sei_ct_type==0 interlaced_frame is left at whichever value it was
>> previously it was guessed based on field/frame coding
>
> Thank you for your patience. I finally understand.
> A new patch attached. Soft telecine is flagged progressive.
no, i dont think it is
the pic_struct used by this file is probably also used by soft telecine
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
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