所以我正在尝试编写一个查看JSON文件的脚本，并检查索引为1的流是否存在。现在我的程序没有这样做。这是程序本身。我想检查(data["streams"][1])是否存在以及是否存在打印编解码器，采样率和所有可用音频流的比特率。
#!/usr/bin/env python
import subprocess
import json
import os.path
# Saving the file path and the name path into input_file
input_file = raw_input("Please enter the input file path: ")
# Loop until the user enters a valid input file
while os.path.isfile(input_file) == False:
print "Please try again, the specified file / path don't exist!"
input_file = raw_input("Please enter the input file path again: ")
# Execution of the ffprobe command to list the general statistics of the file. I have separated both scripts because the script for analyzing the frames is taking longer time.
returned_data = subprocess.check_output(['ffprobe', '-v', 'quiet', '-print_format', 'json', '-show_format', '-show_streams', input_file])
# Loading of the json file
data = json.loads(returned_data.decode('utf-8'))
t = (data["streams"][0]["avg_frame_rate"])
fps = [float(x) for x in t.split('/')]
# Printing of the general information about the video file
print "========================== Video ============================="
print
print "Codec: %s" %(data["streams"][0]["codec_long_name"])
print "Profile: %s" %(data["streams"][0]["profile"])
print "Resolution: %d x %d" %((data["streams"][0]["width"]), (data["streams"][0]["height"]))
print "Pixel Format: %s" %(data["streams"][0]["pix_fmt"])
print "Bits per sample: %s" %(data["streams"][0]["bits_per_raw_sample"])
print
print "========================== Audio ============================="
print
print "Codec: %s" %(data["streams"][1]["codec_name"])
print "Sample Rate: %.3f KHz" %(int(data["streams"][1]["sample_rate"])/1000)
print "Bitrate: %d Kbps" %(int(data["streams"][1]["bit_rate"])/1000)
这是JSON文件的输出。
{
"streams": [
{
"index": 0,
"codec_name": "mpeg4",
"codec_long_name": "MPEG-4 part 2",
"profile": "Simple Profile",
"codec_type": "video",
"codec_time_base": "1/24",
"codec_tag_string": "FMP4",
"codec_tag": "0x34504d46",
"width": 854,
"height": 480,
"coded_width": 854,
"coded_height": 480,
"has_b_frames": 0,
"sample_aspect_ratio": "1:1",
"display_aspect_ratio": "427:240",
"pix_fmt": "yuv420p",
"level": 1,
"chroma_location": "left",
"refs": 1,
"quarter_sample": "false",
"divx_packed": "false",
"r_frame_rate": "24/1",
"avg_frame_rate": "24/1",
"time_base": "1/24",
"start_pts": 0,
"start_time": "0.000000",
"duration_ts": 14315,
"duration": "596.458333",
"bit_rate": "2500431",
"nb_frames": "14315",
"disposition": {
"default": 0,
"dub": 0,
"original": 0,
"comment": 0,
"lyrics": 0,
"karaoke": 0,
"forced": 0,
"hearing_impaired": 0,
"visual_impaired": 0,
"clean_effects": 0,
"attached_pic": 0,
"timed_thumbnails": 0
}
},
{
"index": 1,
"codec_name": "ac3",
"codec_long_name": "ATSC A/52A (AC-3)",
"codec_type": "audio",
"codec_time_base": "1/48000",
"codec_tag_string": "[0] [0][0]",
"codec_tag": "0x2000",
"sample_fmt": "fltp",
"sample_rate": "48000",
"channels": 6,
"channel_layout": "5.1(side)",
"bits_per_sample": 0,
"dmix_mode": "-1",
答案 0 :(得分：0)
你应该可以简单地使用：
if data["streams"][1]:
print(..........)
答案 1 :(得分：0)
您可以使用len函数检查列表中是否存在特定索引。类似的东西：
if len(data["streams"]) > 1:
print data["streams"][1]
答案 2 :(得分：0)
我已经解决了我的问题:)
for i in range(1, len(data["streams"])):
if (data["streams"][i]["codec_type"]) == "audio":
print
print "Audio Channel Number: %d" %(i)
print "Codec: %s" %(data["streams"][i]["codec_name"])
print "Sample Rate: %.3f KHz" %(int(data["streams"][i]["sample_rate"])/1000)
print "Bitrate: %d Kbps" %(int(data["streams"][i]["bit_rate"])/1000)
print
else:
print
print "No valid audio streams!"
print
答案 3 :(得分：0)
你可以简单地使用
if data["streams"][1]:
答案 4 :(得分：0)
安全
<table>
<tr>
<th style="background-color: #007CE2">
Test
</th>
<th style="background-color: #E54040">
Test
</th>
</tr>
<tr>
<td style="background-color: #007CE2">
<p id="t1_list">test<br>another<br>testing</p>
<input type="text" name="t1_input" id="t1_input">
<button>
Add
</button>
</td>
<td style="background-color: #E54040">
<p id="t2_list"></p>
<div class="value_input2">
<input type="text" name="t2_input" id="t2_input">
<button>
Add
</button>
</div>
</td>
</tr>
<tr>
<th style="background-color: #8BC34A">
Test
</th>
<th style="background-color: #FF9800">
Test
</th>
</tr>
<tr>
<td style="background-color: #8BC34A">
<p id="t3_list"></p>
<input type="text" name="t3_input" id="t3_input">
<button>
Add
</button>
</td>
<td style="background-color: #FF9800">
<p id="t4_list"></p>
<input type="text" name="t4_input" id="t4_input">
<button>
Add
</button>
</td>
</tr>
</table>
如果超过1个索引为1的文件（似乎不太可能）松开break语句
for i in range(len(data["streams"])):
if "index" in data["streams"][i].keys() and data["streams"][i]["index"]==1:
try:
print "Codec: %s" %(data["streams"][i]["codec_name"])
print "Sample Rate: %.3f KHz" %(int(data["streams"][i]["sample_rate"])/1000)
print "Bitrate: %d Kbps" %(int(data["streams"][i]["bit_rate"])/1000)
except:
pass
break
如果您确定如果索引1存在，那么比特率，采样率和编解码器将始终存在松散的try catch
for i in range(len(data["streams"])):
if "index" in data["streams"][i].keys() and data["streams"][i]["index"]==1:
try:
print "Codec: %s" %(data["streams"][i]["codec_name"])
print "Sample Rate: %.3f KHz" %(int(data["streams"][i]["sample_rate"])/1000)
print "Bitrate: %d Kbps" %(int(data["streams"][i]["bit_rate"])/1000)
except:
pass
如果你知道如果数据[“streams”]中的元素松散了第一个条件，那么“index”将永远存在
for i in range(len(data["streams"])):
if "index" in data["streams"][i].keys() and data["streams"][i]["index"]==1:
print "Codec: %s" %(data["streams"][i]["codec_name"])
print "Sample Rate: %.3f KHz" %(int(data["streams"][i]["sample_rate"])/1000)
print "Bitrate: %d Kbps" %(int(data["streams"][i]["bit_rate"])/1000)
如果您现在只有索引0出现时才会出现索引1并且始终出现在数据[“streams”]数组中的位置1
for i in range(len(data["streams"])):
if data["streams"][i]["index"]==1:
print "Codec: %s" %(data["streams"][i]["codec_name"])
print "Sample Rate: %.3f KHz" %(int(data["streams"][i]["sample_rate"])/1000)
print "Bitrate: %d Kbps" %(int(data["streams"][i]["bit_rate"])/1000)