[Live-devel] Full HD Contents. trickplay question (with VLC)

[Markus Schumann]

Peng,



I see that the frame rate is set to 29.97 ( 60000 / 1001 / 2) but I don't see any other timing information.

Did you get the file to work?



Markus.





   seq_parameter_set_data()

      profile_idc = 100

      constraint_set0_flag = false

      constraint_set1_flag = false

      constraint_set2_flag = false

      constraint_set3_flag = false

     level_idc = 40

      seq_parameter_set_id = 0

      chroma_format_idc = 1

      bit_depth_luma_minus8 = 0

      bit_depth_chroma_minus8 = 0

      qpprime_y_zero_transform_bypass_flag = false

      seq_scaling_matrix_present_flag = false

      log2_max_frame_num_minus4 = 1

      pic_order_cnt_type = 0

      log2_max_pic_order_cnt_lsb_minus4 = 0

      num_ref_frames = 4

      gaps_in_frame_num_value_allowed_flag = false

      pic_width_in_mbs_minus1 = 119

      pic_height_in_map_units_minus1 = 33

      frame_mbs_only_flag = false

      mb_adaptive_frame_field_flag = true

      direct_8x8_inference_flag = true

      frame_cropping_flag = true

         frame_crop_left_offset = 0

         frame_crop_right_offset = 0

         frame_crop_top_offset = 0

         frame_crop_bottom_offset = 2

      vui_parameters_present_flag = true

      vui_parameters

         aspect_ratio_info_present_flag = true

            aspect_ratio_idc = 1

         overscan_info_present_flag = true

         overscan_appropriate_flag = false

         video_signal_type_present_flag = true

            video_format = 5

            video_full_range_flag = false

            colour_description_present_flag = true

               colour_primaries = 1

               transfer_characteristics = 1

               matrix_coefficients = 1

         chroma_loc_info_present_flag = false

         timing_info_present_flag = true

            num_units_in_tick = 1001

            time_scale = 60000

            fixed_frame_rate_flag = true







H.264 SEI [offset 0x3B82A]

   nal_unit()

      forbidden_zero_bit = '0'

      nal_ref_idc = 0

      nal_unit_type = 6

   pic_timing

      cpb_removal_delay = 2

      dpb_output_delay = 0

      pic_struct = 3

      clock_timestamp[0]

         clock_timestamp_flag = false

      clock_timestamp[1]

         clock_timestamp_flag = false



-----Original Message-----
From: live-devel-bounces at ns.live555.com [mailto:live-devel-bounces at ns.live555.com] On Behalf Of Peng
Sent: Sunday, June 30, 2013 2:43 AM
To: live-devel at ns.live555.com
Subject: Re: [Live-devel] Full HD Contents. trickplay question (with VLC)





>> Note the file "ChunMyung1.ts".  This file was created by applying 'trick play' to the original file, with a scale factor of 1 - i.e., by running:

>>             testMPEG2TransportStreamTrickPlay ChunMyung.ts 0 1

>> ChunMyung1.ts Because our 'trick play' works by using I-frames only, this file effectively consists just of the i-frames from the original file.  If you play this file in VLC, you can see that the I-frames freeze starting at about the 10 second mark, and do not resume until about the 1 minute mark.  Does anyone know why?

>>

>> For another illustration of this, note the file "ChunMyung1-30.ts".  This file was created by applying 'trick play' to the original file, with a scale factor of 1, but starting at the 30 second mark - i.e., by running:

>>             testMPEG2TransportStreamTrickPlay ChunMyung.ts 30 1

>> ChunMyung1-30.ts If you play this file in VLC, you can see that the video is 'empty' until about the 30 second mark (i.e., corresponding to about 1 minute into the original video).  Does anyone know why?

Hi, Ross.



I just check ChunMyung.ts and ChunMyung1-30.ts. The empty 30 seconds has nothing to do with MPEG-TS container, it is caused by picture timing information carried within SPS and SEI of H.264 encoding. This point is that though testMPEG2TransportStreamTrickPlay picks I frames out, it does not modify the associated timing information accordingly.



A feasible method to avoid this is to remove vui_parameters() (possibly together with hrd_parameters()) in SPS and to remove SEI completely. It seems that somebody has already done something very similar:

http://forum.doom9.org/showthread.php?t=152419



Regards



--

Peng



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