1. H.264/AVC code
tracing REPORT
Group 1. no Tsao

2. Overview 1.encode_one_frame 2.encode_enhancement_layer
Main
encode_one_redundant_frame
Encode_enhancement_layer

3. encode_one_frame YES NO NO YES replace_top_pic_with_frame
START
initialization
依之前選擇FIELD_CODING 與 ADAPTIVE_CODING的取向, store_picture_in_dpb
(decode picture buffer) or
replace_top_pic_with_frame
YES
Field picture編碼
FIELD_CODING NO
writeout picture
Frame picture編碼 收尾 NO
ADAPTIVE_CODING
YES
return
Field picture編碼
比較Field picture 與Frame picture 那一個效果好,
並更新context

4. encode_one_frame initialization
START
START TIMER
1.start time ms
2.start time s
PaddAutoCropBorders()
填補picture的邊界, 因為
其邊界不見得一定為
macroblock/macroblock pair
size的倍數
put_buffer_frame()
把指標指向frame structure, 但注意其中不該包含field結構
設定direct mode與deblocking filter的參數
init_frame()
初始化一個new frame
的參數
有input->sp2_frame_indicator NO
CalculateFrameNumber()
計算img-> & input-> 的absolute frame number
YES
sp2_frame_indicator=1
sp2_frame_indicator=0
ReadOneFrame()
利用buf2img()
從file裡讀取一個frame
read_SP_coefficients()
讀取SP frames的係數
initialization 結束

5. encode_one_frame YES NO NO YES replace_top_pic_with_frame
START
initialization
依之前選擇FIELD_CODING 與 ADAPTIVE_CODING的取向, store_picture_in_dpb
(decode picture buffer) or
replace_top_pic_with_frame
YES
Field picture編碼
FIELD_CODING NO
writeout picture
Frame picture編碼 收尾 NO
ADAPTIVE_CODING
YES
return
Field picture編碼
比較Field picture 與Frame picture 那一個效果好,
並更新context

6. encode_one_frame : Field Encoding
START
if ( input->RCEnable )
generic_RC->FieldControl=1
img->field_picture = 1
field_picture (top_pic, bottom_pic)
利用top與bottom field, encode a field picture
img->fld_flag = 1
field encoding完成,
set flag
Field Encoding 結束

7. encode_one_frame :NOT Field Encoding
updateQP()
以rc mode決定updateQP的type
會影響each frame的quantization
parameter
START
if ( input->RCEnable )
generic_RC->FieldControl=0
frame_picture ()
encode a frame picture if
if (input->MbInterlace)
mb_adaptive = 1
rdPictureCoding()
對同一個picture在不同狀態下, 執行multi-pass encoding
else
img->field_picture = 0
encode a frame picture if
output_SP_coefficients()
如果是SP slice的話, output 其coefficients
if(input->RCEnable)
依input->RDPictureDecision可能執行
copy_rc_jvt( quadratic_RC_init, quadratic_RC )
與copy_rc_generic( generic_RC_init, generic_RC )
to copy jvt(joint video team) rate control objects
else
if (input->MbInterlace)
mb_adaptive = 0
如果待會要進行
field code, 要把MB level field/frame coding flag turn off
rc_init_pict()
initialize one picture
NOT Field Encoding 結束

8. encode_one_frame :Adaptive Encoding
START
if ( input->RCEnable )
generic_RC->FieldControl=1
img->write_macroblock = 0
img->bot_MB = 0
encode field,
img->field_picture = 1
update_field_frame_contexts (img->fld_flag)
決定要set的是frame context
or field context
if (input-> RCEnable)
以fld_flag決定
generic_RC->FieldFrame 0 or 1
field_picture ()
encode a field picture
dis_fld
dis_frm
Adaptive Encoding結束
picture_structure_decision()
傳入frame_pic, top_pic,
bottom_pic
呼叫decide_fld_frame()
決定fld_flag 0 or 1

9. encode_one_frame YES NO NO YES replace_top_pic_with_frame
START
initialization
依之前選擇FIELD_CODING 與 ADAPTIVE_CODING的取向, store_picture_in_dpb
(decode picture buffer) or
replace_top_pic_with_frame
YES
Field picture編碼
FIELD_CODING NO
writeout picture
Frame picture編碼 收尾 NO
ADAPTIVE_CODING
YES
return
Field picture編碼
比較Field picture 與Frame picture 那一個效果好,
並更新context

10. encode_one_frame:output
START
img->fld_flag
field mode
frame mode
field_mod_buffer()
設定field mode buffer
frame_mod_buffer()
設定frame mode buffer
writeout picture()
輸入top_pic, bottom_pic
輸出buffer內的encoded picture
writeout picture()
根據rd_pass的值
write out a picture
free_slice_list()
把buffer清空
if(input->RCEnable)
rc_update_pict_frame()
更新rate control 參數
END

11. encode_one_frame YES NO NO YES replace_top_pic_with_frame
START
initialization
依之前選擇FIELD_CODING 與 ADAPTIVE_CODING的取向, store_picture_in_dpb
(decode picture buffer) or
replace_top_pic_with_frame
YES
Field picture編碼
FIELD_CODING NO
writeout picture
Frame picture編碼 收尾 NO
ADAPTIVE_CODING
YES
return
Field picture編碼
比較Field picture 與Frame picture 那一個效果好,
並更新context

12. encode_one_frame:收尾1 如果是frame_coding find_snr () redundant pictures
UpdateDecoders() 模擬packet loss的狀態
UpdatePixelMap()
find_snr ()
Calculate PSNR for Y, U and V.
redundant pictures
save reconstruction to calculate SNR and replace reference picture
stop 2 timers

13. encode_one_frame:收尾2 如果是adaptive_coding else
store_picture_in_dpb() store bottom field in decoded picture buffer
free_storable_picture() 將picture清掉
或replace_top_pic_with_frame () replace top pic with frame
else
store_picture_in_dpb (frame 或 bottom pics, 端看rd_pass)
free_storable_picture()
Report( I_SLICE or SP_SLICE or B_SLICE )
UpdateRCModel

14. Overview 1.encode_one_frame 2.encode_enhancement_layer
Main
encode_one_redundant_frame
Encode_enhancement_layer

15. encode_enhancement_layer-功能
以HierarchicalCoding決定
1.encoding order
2.自訂的encoding order
order決定完成, Encoding B frames

16. encode_enhancement_layer-hierarchicalCoding(1) create_hierarchy() 1.

17. encode_enhancement_layer-hierarchicalCoding(2)

18. encode_enhancement_layer-hierarchicalCoding(3)
User decides.

19. encode_enhancement_layer- Code Structure
if(input->HierarchicalCoding) set the parameter delta_pic_order_cnt[0] encode_one_frame() else

20. encode_enhancement_layer- important variables
IMG_NUMBER: #define IMG_NUMBER (img->number - start_frame_no_in_this_IGOP) <global.h> img->number:current image number to be encoded input->sucessive_Bframe: number of B frame will be used

21. input->BRefPictures:B coded reference pictures replace P pictures (0: not used, 1: used) input->NumFramesInELSubSeq number of frames in the Enhanced Scalability Layer. 0 (default) means that no Enhancement Layer is used.

22. encode_enhancement_layer- setting values
img->frame_num
該frame的編號
img->nal_reference_idc
標示其會不會被refernce到
img->bottompoc
pic order count of bottom field of a frame
img->b_frame_to_code
被encode的b frame編號
img->b_interval

23. setting values
NALU_PRIORITY_HIGH

24. encode_enhancement_layer-example

25. encode_enhancement_layer-other ordering principle
對每一個intra_period,通知client decoder去 清空buffer