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有些流具有多个 #269

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alexliyu7352
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有些流
pmt->stream_count == sizeof(pmt->streams) / sizeof(pmt->streams[0]) 这时不应该直接报错, 而是可以继续播放下去的

有些流
pmt->stream_count == sizeof(pmt->streams) / sizeof(pmt->streams[0])
这时不应该直接报错, 而是可以继续播放下去的
@ireader
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ireader commented Apr 9, 2023

默认一个节目最多4个流(video + audio + subtitle + private stream)

  • 如果特定场景下需要多个流, 可以调整pmt中的stream_count数值;
  • 一般IPTV场景下, 建议使用多个节目, PAT的节目表是没有限制的, 可以有几百路节目;

@alexliyu7352
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对, 所以这里是否直接断言终止了有点不合理吧?
因为有时候源方是无法控制的.

@alexliyu7352
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还有假设一个节目4个流,
pmt->stream_count == 4
sizeof(pmt->streams) / sizeof(pmt->streams[0]) == 4

这时候就触发断言了阿

@ireader
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ireader commented Apr 9, 2023

还有假设一个节目4个流, pmt->stream_count == 4 sizeof(pmt->streams) / sizeof(pmt->streams[0]) == 4

这时候就触发断言了阿

    for(i = 0; i < pmt->stream_count; i++)
    {
        if(pmt->streams[i].pid == pid)
            return &pmt->streams[i];
    }
    
    if(pmt->stream_count >= sizeof(pmt->streams) / sizeof(pmt->streams[0]))
    {
        assert(0);
        return NULL;
    }

这里的逻辑是最多支持4个stream。

@ireader
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ireader commented Apr 9, 2023

对, 所以这里是否直接断言终止了有点不合理吧? 因为有时候源方是无法控制的.

这里要根据实际情况来处理, 大部分场景下,4个stream就够了;如果源流确实有超过4个stream,可以把streams数组调大一些。

假如实际源流的单个节目中超过了4个stream,直接覆盖最后一个stream不是最好的处理策略,因为覆盖实际上意味着丢失了一路stream。

@ireader
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ireader commented Apr 9, 2023

image

如果源流中音视频编码格式或者参数发生变化,可以考虑把135/136行注释放开。

按照TS规范,PMT中version number发生变化时应该需要更新流信息,pmt_clear可以清除之前的流信息。 但是国内有些厂商生成的TS流不太规范,version number一直变化,调用pmt_clear可能会造成组帧失败,所以默认把这行关闭了。

@ireader
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ireader commented Apr 9, 2023

image

当时做了个兼容策略如上

@alexliyu7352
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streams数组调大的确可以解决, 但是有时候是不知道track数量的, 有些流可能一个视频track带5-6个不同语言的音频track.
所以总不好streams数组调整的很大.

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