如何在Python语言中使用subprocess.run运行包含引号的tsduck shell命令

Question

以下是tsduck手册中编写的命令：

tsp -I dvb -a 1 @ts1028.txt \
     -P svremove -s AlJazeeraEnglish \
     -P merge "tsp -I dvb -a 0 @ts1022.txt -P zap TV5MondeEurope" \
     -P analyze -i 30 -o merged.txt \
     -O dektec @modulation.txt

以下是我的版本：

import sys
import subprocess

mod_values = { "bandwidth":             "8-mhz",
               "convolutional_rate":    "7/8",
               "frequency":             "578000000",
               "guard_interval":        "1/4",
               "dmb_constellation":     "64-QAM",
               "modulation":            "DVB-T"}

tsterinfo_rate = subprocess.run(['tsterinfo',
    "-h", mod_values["convolutional_rate"],
    "-g", mod_values["guard_interval"],
    "-c", mod_values["dmb_constellation"],
    "-s"], stdout=subprocess.PIPE, universal_newlines=True)

mod_values["dvb_bitrate"] = tsterinfo_rate.stdout

infile=sys.argv[1]

run_tsp = subprocess.run(['tsp',
    '--verbose',
    '-b', mod_values["dvb_bitrate"],
    '-I', 'null',
    '-P', 'merge',
        f'"tsp -I File {infile} --infinite"',
    '-P', 'pcrbitrate',
    '-P', 'regulate',
    '-O', 'dektec',
    '--frequency', mod_values["frequency"],
    '--modulation', mod_values["modulation"],
    '--guard-interval', mod_values["guard_interval"],
    '--convolutional-rate', mod_values["convolutional_rate"],
    '--dmb-constellation', mod_values["dmb_constellation"],
    '-s'])

如果我尝试将命令中的引号部分保留为完整字符串，并在单引号中包含空格，则命令中的引号部分将返回此错误：

/bin/sh: 1: tsp -I File ../Videos/myts.ts --infinite: not found

在没有引号的情况下，它会错误地说输入太多，就像没有引号直接进入终端一样

python 3.8.5，ubuntu 20.04

Answer 1

在完成这项工作时，我发现我的tsp命令有一些错误。关于将引号传递给子流程的问题的答案似乎可以通过使用

shell=True

在子进程选项中。然后，您可以将命令行参数作为一个大字符串而不是列表进行传递。

我将传输流作为参数并创建CBR输出以便通过Dektec DTU-215进行处理的最后一个脚本是：

    import sys
    import subprocess
    import json
    
    # set modulation parameters in dict in order to reference once for bitrate calc and use again for modulator setup
    mod_values = { "bandwidth":             "8-mhz",
                   "convolutional_rate":    "7/8",
                   "frequency":             "578000000",
                   "guard_interval":        "1/4",
                   "dmb_constellation":     "64-QAM",
                   "modulation":            "DVB-T"}
    
    # calculate modulated bitrate and add to dict
    tsterinfo_rate = subprocess.run(['tsterinfo',
        "-h", mod_values["convolutional_rate"],
        "-g", mod_values["guard_interval"],
        "-c", mod_values["dmb_constellation"],
        "-s"], stdout=subprocess.PIPE, universal_newlines=True)
    
    mod_values["dvb_bitrate"] = tsterinfo_rate.stdout.strip()
    
    # first argument is input file transport stream
    infile=sys.argv[1]
    
    # use mediainfo to calculate bitrate of input ts (must be CBR)
    infile_mediainfo = subprocess.run(["mediainfo",
        "--Output=JSON",
        infile],
        capture_output=True)
    
    print(infile_mediainfo)
    
    media_data = json.loads(infile_mediainfo.stdout)
    
    ts_bitrate = int(media_data["media"]["track"][0]["OverallBitRate"])
    
    print(f'ts_bitrate is: {ts_bitrate}')
    
    # without -t option we don't have a PAT to even merge our stream with
    # packet burst seems to make big difference to how smooth final playback is, default (16 according to docs) was jerky but 14 seems smooth
    run_tsp = subprocess.run(f'tsp \
                    --verbose \
                    -d \
                    -b {mod_values["dvb_bitrate"]} \
                    -I null \
                    -P regulate --packet-burst 14 \
                    -P merge \
                    -t \
                        "tsp -I file {infile} \
                        --infinite \
                        -P regulate -b {ts_bitrate}" \
                    -O dektec \
                    -f {mod_values["frequency"]} \
                    -m {mod_values["modulation"]} \
                    -g {mod_values["guard_interval"]} \
                    -r {mod_values["convolutional_rate"]} \
                    --dmb-constellation {mod_values["dmb_constellation"]} \
                    -s', shell=True)