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69 lines
2.3 KiB
Markdown
69 lines
2.3 KiB
Markdown
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# PL_MPEG - MPEG1 Video decoder, MP2 Audio decoder, MPEG-PS demuxer
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Single-file MIT licensed library for C/C++
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See [pl_mpeg.h](https://github.com/phoboslab/pl_mpeg/blob/master/pl_mpeg.h) for
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the documentation.
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## Why?
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This is meant as a simple way to get video playback into your app or game. Other
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solutions, such as ffmpeg require huge libraries and a lot of glue code.
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MPEG1 is an old and inefficient codec, but it's still good enough for many use
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cases. All patents related to MPEG1 and MP2 have expired, so it's completely
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free now.
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This library does not make use of any SIMD instructions, but because of
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the relative simplicity of the codec it still manages to decode 4k60fps video
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on a single CPU core (on my i7-6700k at least).
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## Compilation on Linux
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Use a GCC invocation like the following to build the example `pl_mpeg_player`
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program:
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```shell
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gcc -o pl_mpeg_player pl_mpeg_player.c $(pkg-config --cflags --libs sdl2 glew)
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```
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## Example Usage
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- [pl_mpeg_extract_frames.c](https://github.com/phoboslab/pl_mpeg/blob/master/pl_mpeg_extract_frames.c)
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extracts all frames from a video and saves them as PNG.
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- [pl_mpeg_player.c](https://github.com/phoboslab/pl_mpeg/blob/master/pl_mpeg_player.c)
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implements a video player using SDL2 and OpenGL for rendering.
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## Encoding for PL_MPEG
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Most [MPEG-PS](https://en.wikipedia.org/wiki/MPEG_program_stream) (`.mpg`) files
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containing MPEG1 Video ("mpeg1") and MPEG1 Audio Layer II ("mp2") streams should
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work with PL_MPEG. Note that `.mpg` files can also contain MPEG2 Video, which is
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not supported by this library.
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You can encode video in a suitable format using ffmpeg:
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```
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ffmpeg -i input.mp4 -c:v mpeg1video -q:v 0 -c:a mp2 -format mpeg output.mpg
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```
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`-q:v` sets a fixed video quality with a variable bitrate, where `0` is the
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highest. You may use `-b:v` to set a fixed bitrate instead; e.g.
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`-b:v 2000k` for 2000 kbit/s. Please refer to the
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[ffmpeg documentation](http://ffmpeg.org/ffmpeg.html#Options) for more details.
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If you just want to quickly test the library, try this file:
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https://phoboslab.org/files/bjork-all-is-full-of-love.mpg
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## Limitations
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- no error reporting. PL_MPEG will silently ignore any invalid data.
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- the pts (presentation time stamp) for packets in the MPEG-PS container is
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ignored. This may cause sync issues with some files.
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- bugs, probably.
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