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• Generate benchmark table

  22 juillet 2020, par Saurabh P Bhandari

  I have generated benchmarks for comparing two approaches taken for scaling video files using ffmpeg tool.

  


  The benchmarks are logged in this format :

  


  x.mp4 Output_Resolution : 10 p

Parameter1 : a

Method : A

real    0m5.788s
user    0m16.112s
sys     0m0.313s

Method : B, ParameterB1 : b11

ParameterB2 : b21

real    0m6.637s
user    0m16.618s
sys     0m0.720s

ParameterB2 : b22

real    0m5.486s
user    0m17.570s
sys     0m0.568s

ParameterB2 : b23

real    0m5.232s
user    0m18.212s
sys     0m0.718s

Method : B, ParameterB1 : b12

ParameterB2 : b21

real    0m6.398s
user    0m16.790s
sys     0m0.528s

ParameterB2 : b22

real    0m5.449s
user    0m17.229s
sys     0m0.533s

ParameterB2 : b23

real    0m5.275s
user    0m18.411s
sys     0m0.522s

##################################################################################################################

Parameter1 : b

Method : A

real    0m5.927s
user    0m16.451s
sys     0m0.308s

Method : B, ParameterB1 : b11

ParameterB2 : b21

real    0m6.685s
user    0m17.044s
sys     0m0.597s

ParameterB2 : b22

real    0m5.942s
user    0m18.971s
sys     0m0.804s

ParameterB2 : b23

real    0m6.119s
user    0m20.869s
sys     0m0.792s

.
.
.



  


  There are two methods (A and B). Method A and B share Parameter1 which can take values a,b,c....
Method B has other parameters B1 and B2. ParameterB1 and ParameterB2 take values b11,b12,b13... and b21,b22,b23... respectively. A line separator (which consists of multiple #) is used to separate the measurements for different values of Parameter1.

  


  I would like to view the benchmarks in tabular format.

  


  +--------+---------------------------------------+----------------+----------------+----------------+
| Method |                                       | Parameter1 (a) | Parameter1 (b) | Parameter1 (c) |
+--------+---------------------------------------+----------------+----------------+----------------+
|    A   |                   NA                  | 4.03s          | 3.23s          | 1.4s           |
+--------+-------------------+-------------------+----------------+----------------+----------------+
|    B   | ParameterB1 (b11) | ParameterB2 (b21) | .              |                |                |
|        |                   +-------------------+----------------+----------------+----------------+
|        |                   | ParameterB2 (b22) | .              |                |                |
|        |                   +-------------------+----------------+----------------+----------------+
|        |                   | ParameterB2 (b23) | .              |                |                |
|        +-------------------+-------------------+----------------+----------------+----------------+
|        | ParameterB1 (b12) | ParameterB2 (b21) | .              |                |                |
|        |                   +-------------------+----------------+----------------+----------------+
|        |                   | ParameterB2 (b22) | .              |                |                |
|        |                   +-------------------+----------------+----------------+----------------+
|        |                   | ParameterB2 (b23) | .              |                |                |
|        +-------------------+-------------------+----------------+----------------+----------------+
|        | ParameterB1 (b12) | ParameterB2 (b21) | .              |                |                |
|        |                   +-------------------+----------------+----------------+----------------+
|        |                   | ParameterB2 (b22) | .              |                |                |
|        |                   +-------------------+----------------+----------------+----------------+
|        |                   | ParameterB2 (b23) | .              |                |                |
+--------+-------------------+-------------------+----------------+----------------+----------------+


  


  The cell values consists of the real time values in seconds (real 0m6.119s).

  


  How can I generate such a table using python ?

  


  ---

  


  I have written a "not-so-efficient" python script with the help from a previous answer from a similar question I asked a few months ago.

  


  import pprint

def gettime(x):
    m,s = map(float,x[:-1].split('m'))
    return 60 * m + s

with open("log") as fp:
    lines = fp.read().splitlines()

idx = 0
A = {}
B = {}

while idx < len(lines):
    if "Parameter1" in lines[idx]:
        Parameter1 = lines[idx].split(' ')[-1]
        temp1 = {}
        idx += 2
        if "A" in lines[idx]:
            idx += 2
            A[Parameter1] = gettime(lines[idx].split('\t')[-1])
            while idx < len(lines):
                if "B" in lines[idx]:
                    ParameterB1 = lines[idx].split(' ')[-1]
                    temp2 = {}
                    idx += 1
                    while idx < len(lines):
                        if "ParameterB2" in lines[idx]:
                            ParameterB2 = lines[idx].split(' ')[-1]
                            idx += 2
                            temp2[ParameterB2] = gettime(lines[idx].split('\t')[-1])
                        elif "#" in lines[idx] or "B" in lines[idx]:
                            break
                        idx += 1
                    temp1[ParameterB1] = temp2
                elif "#" in lines[idx]:
                    B[Parameter1] = temp1
                    break
                else:
                    idx += 1
    else:
        idx += 1
        
print("A")
print(A)

pp = pprint.PrettyPrinter(sort_dicts = False, depth = 4)
print("B")
pp.pprint(B)


  


  This script parses the log and stores the measurements obtained for respective methods and parameters in a dictionary.

  


  Example output from the script :

  


  A
{'a': 4.03, 'b': 3.23, 'c': 1.4}
B
{'a': {'b21': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0},
       'b22': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0},
       'b23': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0}},
 'b': {'b21': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0},
       'b22': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0},
       'b23': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0}},
 'c': {'b21': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0},
       'b22': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0},
       'b23': {'b11': 0.0, 'b12': 0.0, 'b13': 0.0}}}


  


  How can I print this in tabular format as described above ?

  


• avcodec/libzvbi-teletextdec : fix txt_default_region limits

  9 juin 2020, par Marton Balint

  avcodec/libzvbi-teletextdec : fix txt_default_region limits
  Max region ID is 87. Also the region affects not only the G0 charset but G2 and
  
  the national subset as well.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] doc/decoders.texi
  • [DH] libavcodec/libzvbi-teletextdec.c

• ffmpeg - detect frames that have a given image/logo

  13 juillet 2012, par sofia

  I'm trying to split a video by detecting the presence of a marker (an image) in the frames. I've gone over the documentation and I see removelogo but not detectlogo ;)

  Does anyone know how this could be achieved ? I know what the logo is and the region it will be on.

  I'm thinking i can extract all frames to png's and then analyse them one by one (or n by n) but it might be a lengthy process..

  Any pointers ?

  Thanks :)