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    <p><strong>1</strong> You're reading bytes instead of 16-bit samples in this else branch:</p> <pre><code>while (!feof(infile)) { if (is_8bit) { fread(inbuff8, 1, BUFSIZE, infile); } else { fread(inbuff16, 1, BUFSIZE, infile); // &lt;-- should be BUFSIZE*2 } </code></pre> <p><strong>2</strong> You don't saturate the values when scaling, e.g. original 16-bit sample = 32000 and factor = 1.5 will wrap around the integer value instead of clamping it to the maximum of 32767.</p> <p><strong>3</strong> You don't look at the RIFF and other headers at all. In WAV files, it is possible that the audio data is followed by some informational footers or preceded by additional headers. Or in other words: Your <code>header</code> struct is too static. You should also read the WAV format from the file instead of having a parameter saying it's 8 bit samples.</p> <p><strong>4</strong> This just won't happen:</p> <pre><code> outbuff16[i] = factor * inbuff16[i]; if ((int)outbuff16[i] &gt; MAX_16BIT_AMP) </code></pre> <p>8-bit/16-bit values will never be greater than 255/32768 except if your computer inserts some magic bits into the memory when integers overflows :P</p> <p>And audio samples are signed, so the ranges are -128;127 and -32768;32767. Overflow checking must occur in the multiplication expression. You're also making assumptions on the floating-point-to-integer rounding mode, which is configurable and should be considered. Something like <code>if(roundf(factor * inbuff16[i]) &gt; 32767 || roundf(factor * inbuff16[i]) &lt; -32768)</code>, maybe.</p> <p><strong>5</strong> You don't store the result of <code>fread</code>, so you will write too many samples to the output file.</p> <p><strong>6</strong> And as a last point, you're reinventing the wheel. As long as this is for learning, it's okay. Else you should use existing libraries.</p>
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    1. POprocessing an audio wav file with C
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    1. COI think you caught most things - I would add that sizeof(meta) is wrong when writing out the header as meta is a pointer - needs to be sizeof(header) or sizeof(*meta).
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    2. COthat's great feedback, I'll try these things out
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    3. COre: item 3, you also can't make assumptions based on inspecting the output of your favourite wave editor, as they all have quirks. Apparently much of the work in libsndfile involved working around oddities in various wave editors. If you are comfortable with the libsndfile license, all this reduces to a few sf_read_floats and sf_write_floats with some initializing stuff thrown in.
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