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Autres articles (111)
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Script d’installation automatique de MediaSPIP
25 avril 2011, parAfin de palier aux difficultés d’installation dues principalement aux dépendances logicielles coté serveur, un script d’installation "tout en un" en bash a été créé afin de faciliter cette étape sur un serveur doté d’une distribution Linux compatible.
Vous devez bénéficier d’un accès SSH à votre serveur et d’un compte "root" afin de l’utiliser, ce qui permettra d’installer les dépendances. Contactez votre hébergeur si vous ne disposez pas de cela.
La documentation de l’utilisation du script d’installation (...) -
Le plugin : Gestion de la mutualisation
2 mars 2010, parLe plugin de Gestion de mutualisation permet de gérer les différents canaux de mediaspip depuis un site maître. Il a pour but de fournir une solution pure SPIP afin de remplacer cette ancienne solution.
Installation basique
On installe les fichiers de SPIP sur le serveur.
On ajoute ensuite le plugin "mutualisation" à la racine du site comme décrit ici.
On customise le fichier mes_options.php central comme on le souhaite. Voilà pour l’exemple celui de la plateforme mediaspip.net :
< ?php (...) -
MediaSPIP 0.1 Beta version
25 avril 2011, parMediaSPIP 0.1 beta is the first version of MediaSPIP proclaimed as "usable".
The zip file provided here only contains the sources of MediaSPIP in its standalone version.
To get a working installation, you must manually install all-software dependencies on the server.
If you want to use this archive for an installation in "farm mode", you will also need to proceed to other manual (...)
Sur d’autres sites (4198)
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Reverse Engineering Radius VideoVision
3 avril 2011, par Multimedia Mike — Reverse EngineeringI was called upon to help reverse engineer an old video codec called VideoVision (FourCC : PGVV), ostensibly from a company named Radius. I’m not sure of the details exactly but I think a game developer has a bunch of original FMV data from an old game locked up in this format. The name of the codec sounded familiar. Indeed, we have had a sample in the repository since 2002. Alex B. did some wiki work on the codec some years ago. The wiki mentions that there existed a tool to transcode PGVV data into MJPEG-B data, which is already known and supported by FFmpeg.
The Software
My contacts were able to point me to some software, now safely archived in the PGVV samples directory. There is StudioPlayer2.6.2.sit.hqx which is supposed to be a QuickTime component for working with PGVV data. I can’t even remember how to deal with .sit or .hqx data. Then there is RadiusVVTranscoder101.zip which is the tool that transcodes to MJPEG-B.Disassembling for Reverse Engineering
Since I could actually unpack the transcoder, I set my sights on that. Unpacking the archive sets up a directory structure for a component. There is a binary called RadiusVVTranscoder under RadiusVVTranscoder.component/Contents/MacOS/. Basic deadlisting disassembly is performed via ’otool’ as shown :otool -tV RadiusVVTranscoder | c++filt
This results in a deadlisting of both PowerPC and 32-bit x86 code, as the binary is a "fat" Mac OS X binary designed to run on both architectures. The command line also demangles C++ function signatures which gives useful insight into the parameters passed to a function.
Pretty Pictures
The binary had a lot of descriptive symbols. As a basis for reverse engineering, I constructed call graphs using these symbols. Here are the 2 most relevant portions (click for larger images).The codec initialization generates Huffman tables relevant to the codec :
The main decode function calls AddMJPGFrame which apparently does the heavy lifting for the transcode process :
Based on this tree, I’m guessing that luma blocks can be losslessly transcoded (perhaps with different Huffman tables) which chroma blocks may rely on a different quantization method.
Assembly Constructs
I started looking at the instructions (the x86 ones, of course). The binary uses a calling convention I haven’t seen before, at least not for the x86 : Rather than pushing function arguments onto the stack, the code manually subtracts, e.g., 12 from the ESP register, loads 3 32-bit arguments into memory relative to ESP, and then proceeds with the function call.I’m also a little unclear on constructs such as "call ___i686.get_pc_thunk.bx" seen throughout relevant functions such as MakeRadiusQuantizationTables().
I’m just presenting what I have so far in case anyone else wants to try their hand.
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Dreamcast Development Desktop
28 mars 2011, par Multimedia Mike — Sega DreamcastSome people are curious about what kind of equipment is required to program a Sega Dreamcast. This is my setup :
It’s a bit overcomplicated. The only piece in that picture which doesn’t play a role in the Dreamcast development process is the scanner. The Eee PC does the heavy lifting of development (i.e., text editing and cross compilation) and uploads to the Dreamcast via a special serial cable. Those are the most essential parts and are really the only pieces necessary for a lot of algorithmic stuff (things that can be validated via a serial console). But then I have to go up a level where I output video. That’s where things get messy.
The Mac Mini and giant monitor really just act as a glorified TV in this case. Ideally, it will be more than that. The DC outputs audio and video via composite cables to a Canopus DV capture bridge. That’s connected via FireWire to the external hard drive underneath the Mac Mini, which is connected to the Mac. Adobe Premiere Pro handles the DV capture / display.
One day I hope to have something worthwhile to capture.
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Dumping and playing h264 bytestream from RTSP webcam
18 octobre 2011, par thekMy goal is to connect (rtsp) to camera, get h264 stream from rtp packages, save it as a bytestream to file and be able to play it (with ffplay or vlc). The only problem is that my result stream gives me errors (and a nice gray rectangle, sometimes with something moving - like only P frames are decoded) while playing.
Here is my DESCRIBE response from rtsp server (ip replaced with ) :
10:04:18.387 [New I/O client worker #1-1] INFO rtsp.WebcamClientResponseHandler - Sending DESCRIBE request: DESCRIBE rtsp://<server>:<port>/channel1 RTSP/1.0
-------status---------
200 OK
-------headers---------
CSeq : 2
Date : Wed, Jan 07 2009 19:05:09 GMT
Content-Base : rtsp://<server>/channel1/
Content-Type : application/sdp
Content-Length : 433
-------content---------
v=0
o=- 515949295799 1 IN IP4 <server>
s=Session streamed by stream
i=1
t=0 0
a=tool:LIVE555 Streaming Media v2009.01.26
a=type:broadcast
a=control:*
a=range:npt=0-
a=x-qt-text-nam:Session streamed by stream
a=x-qt-text-inf:1
m=video 0 RTP/AVP 96
c=IN IP4 0.0.0.0
b=AS:128
a=rtpmap:96 H264/90000
a=fmtp:96 packetization-mode=1;profile-level-id=420028;sprop-parameter-sets=Z0IAKOkCg/I=,aM44gA==
a=control:tracks
</server></server></port></server>And server sends me RTP packages with non IDR frames and fragmented (type=28) IDR frames. First ones are written to file, fragmented are unpacked.
The result byte stream is :NAL SPS NAL PPS NAL FRAME1 NAL FRAME2 ... NAL FRAMEN
where NAL is (hex) 00 00 01
and SPS is (decoded Z0IAKOkCg/I= from sprop-parameter-sets): 67 42 00 28 e9 02 83 f2
and PPS is (decoded aM44gA==): 68 ce 38 80I found similar topic with same steps taken :
how-to-process-raw-udp-packets-so-that-they-can-be-decoded-by-a-decoder-filter-i
but I can't see what am I missing.Could anyone give me some clue what may be wrong ?
This is a link to generated h264 file :
a.h264Below I'm attaching some more information from playing my stream.
Playing my video with ffplay -f h264 a.h264 gives me following output (and a gray rectangle) :
ffplay version 0.8.4-4:0.8.4-0ubuntu1~jon1, Copyright (c) 2003-2011 the FFmpeg developers
built on Sep 25 2011 09:45:09 with gcc 4.4.3
configuration: --extra-version='4:0.8.4-0ubuntu1~jon1' --prefix=/usr --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --enable-libvpx --enable-runtime-cpudetect --enable-vaapi --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static
libavutil 51. 9. 1 / 51. 9. 1
libavcodec 53. 7. 0 / 53. 7. 0
libavformat 53. 4. 0 / 53. 4. 0
libavdevice 53. 1. 1 / 53. 1. 1
libavfilter 2. 23. 0 / 2. 23. 0
libswscale 2. 0. 0 / 2. 0. 0
libpostproc 52. 0. 0 / 52. 0. 0
[h264 @ 0x184d4c0] Missing reference picture
[h264 @ 0x184d4c0] decode_slice_header error
[h264 @ 0x184d4c0] concealing 300 DC, 300 AC, 300 MV errors
[h264 @ 0x1822640] max_analyze_duration 5000000 reached at 5000000
[h264 @ 0x1822640] Estimating duration from bitrate, this may be inaccurate
Input #0, h264, from 'a.h264':
Duration: N/A, bitrate: N/A
Stream #0.0: Video: h264 (Baseline), yuv420p, 320x240, 25 fps, 25 tbr, 1200k tbn, 50 tbc
[h264 @ 0x184d4c0] Missing reference pictureq= 3KB sq= 0B f=0/0
[h264 @ 0x184d4c0] decode_slice_header error
[h264 @ 0x184d4c0] concealing 300 DC, 300 AC, 300 MV errors
[h264 @ 0x184d4c0] QP 4294967283 out of rangeKB sq= 0B f=0/0 0/0
[h264 @ 0x184d4c0] decode_slice_header error
[h264 @ 0x184d4c0] concealing 300 DC, 300 AC, 300 MV errors
[h264 @ 0x184d4c0] Missing reference picture
[h264 @ 0x184d4c0] decode_slice_header error
[h264 @ 0x184d4c0] mmco: unref short failure
[h264 @ 0x184d4c0] concealing 300 DC, 300 AC, 300 MV errors
[h264 @ 0x184d4c0] P sub_mb_type 5 out of range at 8 0
[h264 @ 0x184d4c0] error while decoding MB 8 0
[h264 @ 0x184d4c0] concealing 300 DC, 300 AC, 300 MV errors
[h264 @ 0x184d4c0] QP 4294967283 out of range
[h264 @ 0x184d4c0] decode_slice_header error
[h264 @ 0x184d4c0] concealing 300 DC, 300 AC, 300 MV errorsRunning h264_analyse (http://h264bitstream.sourceforge.net/) on my stream gives me :
./h264_analyze a.h264
!! Found NAL at offset 3 (0x0003), size 8 (0x0008)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 3
nal_unit_type : 7 ( Sequence parameter set )
======= SPS =======
profile_idc : 66
constraint_set0_flag : 0
constraint_set1_flag : 0
constraint_set2_flag : 0
constraint_set3_flag : 0
reserved_zero_4bits : 0
level_idc : 40
seq_parameter_set_id : 0
chroma_format_idc : 0
residual_colour_transform_flag : 0
bit_depth_luma_minus8 : 0
bit_depth_chroma_minus8 : 0
qpprime_y_zero_transform_bypass_flag : 0
seq_scaling_matrix_present_flag : 0
log2_max_frame_num_minus4 : 0
pic_order_cnt_type : 0
log2_max_pic_order_cnt_lsb_minus4 : 1
delta_pic_order_always_zero_flag : 0
offset_for_non_ref_pic : 0
offset_for_top_to_bottom_field : 0
num_ref_frames_in_pic_order_cnt_cycle : 0
num_ref_frames : 1
gaps_in_frame_num_value_allowed_flag : 0
pic_width_in_mbs_minus1 : 19
pic_height_in_map_units_minus1 : 14
frame_mbs_only_flag : 1
mb_adaptive_frame_field_flag : 0
direct_8x8_inference_flag : 1
frame_cropping_flag : 0
frame_crop_left_offset : 0
frame_crop_right_offset : 0
frame_crop_top_offset : 0
frame_crop_bottom_offset : 0
vui_parameters_present_flag : 0
=== VUI ===
aspect_ratio_info_present_flag : 0
aspect_ratio_idc : 0
sar_width : 0
sar_height : 0
overscan_info_present_flag : 0
overscan_appropriate_flag : 0
video_signal_type_present_flag : 0
video_format : 0
video_full_range_flag : 0
colour_description_present_flag : 0
colour_primaries : 0
transfer_characteristics : 0
matrix_coefficients : 0
chroma_loc_info_present_flag : 0
chroma_sample_loc_type_top_field : 0
chroma_sample_loc_type_bottom_field : 0
timing_info_present_flag : 0
num_units_in_tick : 0
time_scale : 0
fixed_frame_rate_flag : 0
nal_hrd_parameters_present_flag : 0
vcl_hrd_parameters_present_flag : 0
low_delay_hrd_flag : 0
pic_struct_present_flag : 0
bitstream_restriction_flag : 0
motion_vectors_over_pic_boundaries_flag : 0
max_bytes_per_pic_denom : 0
max_bits_per_mb_denom : 0
log2_max_mv_length_horizontal : 0
log2_max_mv_length_vertical : 0
num_reorder_frames : 0
max_dec_frame_buffering : 0
=== HRD ===
cpb_cnt_minus1 : 0
bit_rate_scale : 0
cpb_size_scale : 0
initial_cpb_removal_delay_length_minus1 : 0
cpb_removal_delay_length_minus1 : 0
dpb_output_delay_length_minus1 : 0
time_offset_length : 0
!! Found NAL at offset 14 (0x000E), size 4 (0x0004)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 3
nal_unit_type : 8 ( Picture parameter set )
======= PPS =======
pic_parameter_set_id : 0
seq_parameter_set_id : 0
entropy_coding_mode_flag : 0
pic_order_present_flag : 0
num_slice_groups_minus1 : 0
slice_group_map_type : 0
num_ref_idx_l0_active_minus1 : 0
num_ref_idx_l1_active_minus1 : 0
weighted_pred_flag : 0
weighted_bipred_idc : 0
pic_init_qp_minus26 : 0
pic_init_qs_minus26 : 0
chroma_qp_index_offset : 0
deblocking_filter_control_present_flag : 0
constrained_intra_pred_flag : 0
redundant_pic_cnt_present_flag : 0
transform_8x8_mode_flag : 1
pic_scaling_matrix_present_flag : 0
second_chroma_qp_index_offset : 16
!! Found NAL at offset 21 (0x0015), size 480 (0x01E0)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 2
nal_unit_type : 1 ( Coded slice of a non-IDR picture )
======= Slice Header =======
first_mb_in_slice : 0
slice_type : 5 ( P slice only )
pic_parameter_set_id : 0
frame_num : 1
field_pic_flag : 0
bottom_field_flag : 0
idr_pic_id : 0
pic_order_cnt_lsb : 2
delta_pic_order_cnt_bottom : 0
redundant_pic_cnt : 0
direct_spatial_mv_pred_flag : 0
num_ref_idx_active_override_flag : 0
num_ref_idx_l0_active_minus1 : 0
num_ref_idx_l1_active_minus1 : 0
cabac_init_idc : 0
slice_qp_delta : -7
sp_for_switch_flag : 0
slice_qs_delta : 0
disable_deblocking_filter_idc : 0
slice_alpha_c0_offset_div2 : 0
slice_beta_offset_div2 : 0
slice_group_change_cycle : 0
=== Prediction Weight Table ===
luma_log2_weight_denom : 0
chroma_log2_weight_denom : 0
luma_weight_l0_flag : 0
chroma_weight_l0_flag : 0
luma_weight_l1_flag : 0
chroma_weight_l1_flag : 0
=== Ref Pic List Reordering ===
ref_pic_list_reordering_flag_l0 : 0
ref_pic_list_reordering_flag_l1 : 0
=== Decoded Ref Pic Marking ===
no_output_of_prior_pics_flag : 0
long_term_reference_flag : 0
adaptive_ref_pic_marking_mode_flag : 0
!! Found NAL at offset 504 (0x01F8), size 324 (0x0144)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 2
nal_unit_type : 1 ( Coded slice of a non-IDR picture )
======= Slice Header =======
first_mb_in_slice : 0
slice_type : 5 ( P slice only )
pic_parameter_set_id : 0
frame_num : 2
field_pic_flag : 0
bottom_field_flag : 0
idr_pic_id : 0
pic_order_cnt_lsb : 4
delta_pic_order_cnt_bottom : 0
redundant_pic_cnt : 0
direct_spatial_mv_pred_flag : 0
num_ref_idx_active_override_flag : 0
num_ref_idx_l0_active_minus1 : 0
num_ref_idx_l1_active_minus1 : 0
cabac_init_idc : 0
slice_qp_delta : -7
sp_for_switch_flag : 0
slice_qs_delta : 0
disable_deblocking_filter_idc : 0
slice_alpha_c0_offset_div2 : 0
slice_beta_offset_div2 : 0
slice_group_change_cycle : 0
=== Prediction Weight Table ===
luma_log2_weight_denom : 0
chroma_log2_weight_denom : 0
luma_weight_l0_flag : 0
chroma_weight_l0_flag : 0
luma_weight_l1_flag : 0
chroma_weight_l1_flag : 0
=== Ref Pic List Reordering ===
ref_pic_list_reordering_flag_l0 : 0
ref_pic_list_reordering_flag_l1 : 0
=== Decoded Ref Pic Marking ===
no_output_of_prior_pics_flag : 0
long_term_reference_flag : 0
adaptive_ref_pic_marking_mode_flag : 0
!! Found NAL at offset 831 (0x033F), size 300 (0x012C)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 2
nal_unit_type : 1 ( Coded slice of a non-IDR picture )
======= Slice Header =======
first_mb_in_slice : 0
slice_type : 5 ( P slice only )
pic_parameter_set_id : 0
frame_num : 3
field_pic_flag : 0
bottom_field_flag : 0
idr_pic_id : 0
pic_order_cnt_lsb : 6
delta_pic_order_cnt_bottom : 0
redundant_pic_cnt : 0
direct_spatial_mv_pred_flag : 0
num_ref_idx_active_override_flag : 0
num_ref_idx_l0_active_minus1 : 0
num_ref_idx_l1_active_minus1 : 0
cabac_init_idc : 0
slice_qp_delta : -7
sp_for_switch_flag : 0
slice_qs_delta : 0
disable_deblocking_filter_idc : 0
slice_alpha_c0_offset_div2 : 0
slice_beta_offset_div2 : 0
slice_group_change_cycle : 0
=== Prediction Weight Table ===
luma_log2_weight_denom : 0
chroma_log2_weight_denom : 0
luma_weight_l0_flag : 0
chroma_weight_l0_flag : 0
luma_weight_l1_flag : 0
chroma_weight_l1_flag : 0
=== Ref Pic List Reordering ===
ref_pic_list_reordering_flag_l0 : 0
ref_pic_list_reordering_flag_l1 : 0
=== Decoded Ref Pic Marking ===
no_output_of_prior_pics_flag : 0
long_term_reference_flag : 0
adaptive_ref_pic_marking_mode_flag : 0
!! Found NAL at offset 1134 (0x046E), size 825 (0x0339)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 2
nal_unit_type : 1 ( Coded slice of a non-IDR picture )
======= Slice Header =======
first_mb_in_slice : 0
slice_type : 5 ( P slice only )
pic_parameter_set_id : 0
frame_num : 4
field_pic_flag : 0
bottom_field_flag : 0
idr_pic_id : 0
pic_order_cnt_lsb : 8
delta_pic_order_cnt_bottom : 0
redundant_pic_cnt : 0
direct_spatial_mv_pred_flag : 0
num_ref_idx_active_override_flag : 0
num_ref_idx_l0_active_minus1 : 0
num_ref_idx_l1_active_minus1 : 0
cabac_init_idc : 0
slice_qp_delta : -9
sp_for_switch_flag : 0
slice_qs_delta : 0
disable_deblocking_filter_idc : 0
slice_alpha_c0_offset_div2 : 0
slice_beta_offset_div2 : 0
slice_group_change_cycle : 0
=== Prediction Weight Table ===
luma_log2_weight_denom : 0
chroma_log2_weight_denom : 0
luma_weight_l0_flag : 0
chroma_weight_l0_flag : 0
luma_weight_l1_flag : 0
chroma_weight_l1_flag : 0
=== Ref Pic List Reordering ===
ref_pic_list_reordering_flag_l0 : 0
ref_pic_list_reordering_flag_l1 : 0
=== Decoded Ref Pic Marking ===
no_output_of_prior_pics_flag : 0
long_term_reference_flag : 0
adaptive_ref_pic_marking_mode_flag : 0
!! Found NAL at offset 1962 (0x07AA), size 754 (0x02F2)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 2
nal_unit_type : 1 ( Coded slice of a non-IDR picture )
======= Slice Header =======
first_mb_in_slice : 0
slice_type : 5 ( P slice only )
pic_parameter_set_id : 0
frame_num : 5
field_pic_flag : 0
bottom_field_flag : 0
idr_pic_id : 0
pic_order_cnt_lsb : 10
delta_pic_order_cnt_bottom : 0
redundant_pic_cnt : 0
direct_spatial_mv_pred_flag : 0
num_ref_idx_active_override_flag : 0
num_ref_idx_l0_active_minus1 : 0
num_ref_idx_l1_active_minus1 : 0
cabac_init_idc : 0
slice_qp_delta : -9
sp_for_switch_flag : 0
slice_qs_delta : 0
disable_deblocking_filter_idc : 0
slice_alpha_c0_offset_div2 : 0
slice_beta_offset_div2 : 0
slice_group_change_cycle : 0
=== Prediction Weight Table ===
luma_log2_weight_denom : 0
chroma_log2_weight_denom : 0
luma_weight_l0_flag : 0
chroma_weight_l0_flag : 0
luma_weight_l1_flag : 0
chroma_weight_l1_flag : 0
=== Ref Pic List Reordering ===
ref_pic_list_reordering_flag_l0 : 0
ref_pic_list_reordering_flag_l1 : 0
=== Decoded Ref Pic Marking ===
no_output_of_prior_pics_flag : 0
long_term_reference_flag : 0
adaptive_ref_pic_marking_mode_flag : 0
!! Found NAL at offset 2719 (0x0A9F), size 824 (0x0338)
==================== NAL ====================
forbidden_zero_bit : 0
nal_ref_idc : 2
nal_unit_type : 1 ( Coded slice of a non-IDR picture )
======= Slice Header =======
first_mb_in_slice : 0
slice_type : 5 ( P slice only )
pic_parameter_set_id : 0
frame_num : 6
field_pic_flag : 0
bottom_field_flag : 0
idr_pic_id : 0
pic_order_cnt_lsb : 12
delta_pic_order_cnt_bottom : 0
redundant_pic_cnt : 0
direct_spatial_mv_pred_flag : 0
num_ref_idx_active_override_flag : 0
num_ref_idx_l0_active_minus1 : 0
num_ref_idx_l1_active_minus1 : 0
cabac_init_idc : 0
slice_qp_delta : -9
sp_for_switch_flag : 0
slice_qs_delta : 0
disable_deblocking_filter_idc : 0
slice_alpha_c0_offset_div2 : 0
slice_beta_offset_div2 : 0
slice_group_change_cycle : 0
=== Prediction Weight Table ===
luma_log2_weight_denom : 0
chroma_log2_weight_denom : 0
luma_weight_l0_flag : 0
chroma_weight_l0_flag : 0
luma_weight_l1_flag : 0
chroma_weight_l1_flag : 0
=== Ref Pic List Reordering ===
ref_pic_list_reordering_flag_l0 : 0
ref_pic_list_reordering_flag_l1 : 0
=== Decoded Ref Pic Marking ===
no_output_of_prior_pics_flag : 0
long_term_reference_flag : 0
adaptive_ref_pic_marking_mode_flag : 0
!! Found NAL at offset 3546 (0x0DDA), size 628 (0x0274)
==================== NAL ====================
[...]
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