HTTP: Failed to download large file recorded with 2GB.

[CodeflowSun]

Description'

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1. SRS version: 4.0'

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2. The log of SRS is as follows:

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HTTP #0 39.152.7.125:25758 GET http://123.6.55.240:18080/live/202112070435020001.2021.12.09.11.30.36.mp4, content-length=-1
[2021-12-09 16:49:38.132][Trace][31841][31w7h85h] http match file=./objs/nginx/html/live/202112070435020001.2021.12.09.11.30.36.mp4, pattern=/, upath=/live/202112070435020001.2021.12.09.11.30.36.mp4
[2021-12-09 16:49:38.132][Trace][31841][31w7h85h] TCP: before dispose resource(HttpStream)(0x20346f0), conns=5, zombies=0, ign=0, inz=0, ind=0
[2021-12-09 16:49:38.132][Error][31841][31w7h85h][11] serve error code=3014 : process request=0 : mux serve : serve http : http mp4 streaming ./objs/nginx/html/live/202112070435020001.2021.12.09.11.30.36.mp4 overflow. size=2846362636, offset=0

3. Specific situation:
   We recorded a video with a duration of 156 minutes in MP4 format. After recording, the video cannot be downloaded. However, after downloading it to the local device via FTP, the video can be played normally using software. The size of the video is 2.65GB.

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Reproduction (Replay)

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1. You can upload a file larger than 2GB to the SRS server.
2. Access through HTTP.

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Expected Behavior
Normal download

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The problem has been found, the key is in srs_app_http_static.cpp:157.

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    if (end == -1) {
        end = (int)(fs->filesize() - 1);
    }
    
    if (end > fs->filesize() || start > end || end < 0) {
        return srs_error_new(ERROR_HTTP_REMUX_OFFSET_OVERFLOW, "http mp4 streaming %s overflow. size=%" PRId64 ", offset=%d",
            fullpath.c_str(), fs->filesize(), start);
    }

The above code is from version 4.0 source code. When performing a type conversion, the "end" of a large file may become negative, causing subsequent exceptions to occur in the handling process.

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TRANS_BY_GPT3

[winlinvip]

Not bad, welcome to submit a PR, bro 👍

TRANS_BY_GPT3

[CodeflowSun]

The PR has been submitted, and the concerns have been mentioned in the PR.
I don't understand C++ and have only made fixes based on my own understanding. I also don't have a testing environment locally, so this bare submission carries risks. Please understand.

TRANS_BY_GPT3

[CodeflowSun]

To briefly explain our current solution, I have not disabled the SRS HTTP service here. We have implemented an MP4 filtering in the outer layer of Nginx. If the request is for an MP4 file, Nginx directly serves as a web server to provide MP4 download service.

TRANS_BY_GPT3