MPEG Player

Introduction

Mpegplayer on Iriver H300, Ipod Photo and Sandisk Sansa e200

mpegplayer is a work-in-progress MPEG video player viewer plugin.

It is currently capable of playing back MPEG-1 and MPEG-2 video streams with MPEG audio multiplexed into .mpg files (MPEG Program Stream).

To play a video file, you just select it in the Rockbox file browser. If your file does not have the .mpg extension, you will need to use the "Open With..." context menu option and choose "mpegplayer.

NOTE: mpegplayer does all video and audio decoding using your device's main CPU. It does not use any special video decoding hardware such as the Broadcom Video Processor found in the ipod Video. mpegplayer therefore performs very badly on such devices in comparison with the manufacturer's original firmware.

Download

Like all plugins documented on this website, mpegplayer is included in the standard Rockbox installation and does not need to be downloaded separately. NOTE: Viewer plugins like mpegplayer do not appear in the Browse Plugins menu - they are launched by selecting a file to be viewed in the normal file browser.

Supported Targets

MPEGPlayer works on all current targets apart from the Archos devices (use PluginVideo instead) and the iriver iFP. However, performance and usability varies greatly - see the following section for performance details.

Performance

The following table shows the speed that mpegplayer can decode the "Elephants Dream" sample video on various targets.

Tests are performed by enabling the Show FPS option and disabling the Limit FPS and Skip Frames options in mpegplayer, playing the video, and then waiting for the FPS to stabilise. Please round the FPS to the nearest whole number.

Player	LCD Size	128x96	128x128	160x96	160x128	176x96	176x128	224x128	224x176	320x176	320x240	Tested on SVN
Sansa c200	132x80
iriver H10 5/6GB	128x128			n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
iriver H10 20GB	160x128	39fps	29fps	32fps	24fps	n/a	n/a	n/a	n/a	n/a	n/a
iriver H120	160x128			30fps	22fps	n/a	n/a	n/a	n/a	n/a	n/a	r16048
iaudio X5	160x128	52fps	39fps	44fps	32fps	n/a	n/a	n/a	n/a	n/a	n/a	r15194
ipod Nano	176x132	57fps	42fps	47fps	35fps	43fps	32fps	n/a	n/a	n/a	n/a	r13490
iriver H300	220x176		41fps	47fps	32fps	42fps	31fps	25fps	18fps	n/a	n/a	r15168
ipod Color/Photo	220x176	55fps	41fps	45fps	33fps	41fps	30fps	25fps	18fps	n/a	n/a
Sansa e200	220x176		59fps					37fps	27fps	n/a	n/a	r16023
ipod Video	320x240	78fps	57fps	65fps	47fps	58fps	43fps	35fps	26fps	19fps	14fps	r15832
Gigabeat	320x240	276fps	212fps	232fps	164fps	210fps	144fps	126fps	92fps	66fps	48fps	r15189

Current limitations

Audio decoding and .mpg file parsing were added to mpegplayer on 1 January 2007. A/V Sync and rebuffering were added in March 2007. Seeking and WVS were added January 2008.

This is still a work-in-progress and is missing the following major features:

• Limited audio samplerate - audio must be sampled at 44.1KHz, other samplerates will play, but at the wrong speed.

Anyone is welcome to download the source and implement these features.

Known Bugs

• A/V Sync - sync is not yet perfect for all files. If you have an example file which plays in sync on a PC video player, but not in mpegplayer (with Limit FPS and Skip Frames) enabled, please post a comment and link in this forum thread.
• USB detection - mpegplayer doesn't react correctly to USB insertion
• End-of-file detection - sometimes mpegplayer will continue playing the file past the end - i.e. jump back to a previously buffered part of the file.
• Backlight whilst charging - mpegplayer doesn't adjust the backlight timeout whilst charging setting, meaning that the backlight may turn off if you're watching a video when charging.
• Quit/Stop problems - sometimes mpegplayer doesn't stop the video when requested, and may not successfully start playback of a subsequent video. (Note by DouglasValentine: Quiting playback from the menu before the end of the video then trying to play the same file again always locks up now fixed on my ipod nano) - FS #6921
• Performance - performance seems to be noticably worse with the current mpegplayer compared to versions prior to rebuffering and av sync. (Note by PaulLouden: I think this can be tracked to the PTS update that checked for changing PTS values)
• Headphone plug detection - When Pause on headphone remove is said, may cause similar problems to USB removal.
• Idle power-off - FS #6091

Note by PaulLouden: Regarding End of File, I think that it may try to stop at the end of file and fail, because often the video will go into slow motion, in a very similar mannery to what has been described to me as happening when USB is inserted, and Headphones are inserted.

Key Mappings during playback

Player	Pause/Resume	Stop	Menu
ipod	PLAY	Long press on PLAY	MENU
iriver H300	ON	OFF	A-B
iaudio X5	PLAY	POWER	REC
Gigabeat	PLAY	A	MENU
iriver H10	PLAY	POWER	REW
Sansa e200	UP	POWER	SELECT

Menu Options

Start Menu

This menu is (optionally) presented before the file starts playing (see Resume Settings)

Play from beginning

Resume information is discarded and the video plays from the start.

Resume time (min): x.x

Resume video playback at stored resume time x.x (start of the video if no resume time is found).

Set start time (min)

A preview screen is presented consisting of a thumbnail preview and a progress bar where the user can select a start time by 'seeking' through the video in 30 second increments. The video playback is started by pressing the select button.

Display Options

Opens submenu - see below.

Quit mpegplayer

Exit the plugin.

Settings Menu

This menu can be accessed from the Start menu orduring video playback, by pressing the "Menu" key during playback. (see "Key Mappings during playback")

Display Options

Opens submenu - see below.

Resume Options

• Resume automatically - Always resume immediately with no prompting
• Play from beginning - Always play file from the beginning.
• Start menu if not completed - Show the start menu if playback was interrupted before finishing (e.g. resume)
• Start menu - Always show the start menu

Clear all resumes: x

Discard all x resume points.

Quit mpegplayer

Exit the plugin.

Display Options Menu

Dithering (default: off)

Prevent banding effects in gradients by blending of colours. (only available on Sansa e200, Sansa c200 and Gigabeat F/X, at this point).

Show FPS (default: off)

This option displays (once a second - if your video is full-screen this means it will get overwritten by the video and appear to flash once per second) the average number of frames decoded per second, the total number of frames skipped (see the Skip Frames option), the current time (in 100Hz ticks) and the time the current frame is due to be displayed.

Limit FPS (default: on)

With this option disabled, mpegplayer will display the video as fast as it can. Useful for benchmarking.

Skip frames (default: on)

This option causes mpegplayer to attempt to maintain realtime playback by skipping the display of frames - but these frames are still decoded. Disabling this option can cause loss of A/V sync.

Sample videos

Elephants Dream

The following files are encoded using mpeg2enc at "-q 6" quantization level. Audio is LAME-encoded MP3 (44.1KHz, Stereo, 170kbps VBR). The source video is the "world's first open movie" - Elephants Dream. It is available under an open license.

Players	LCD Size	1:1 Video	4:3 Video	16:9 Video
iriver H300, ipod Color/Photo & Sansa e200	220x176	n/a	224x176-469kbps	224x128-354kbps
ipod Nano	176x132	n/a	176x128-310kbps	176x96-229kbps
ipod Video & Gigabeat	320x240	n/a	320x240-830kbps	320x176-596kbps
iaudio X5 and iriver H10 20GB	160x128	n/a	160x128-287kbps	160x96-212kbps
iriver H10 5/6GB	128x128	128x128-247kbps	128x96-192kbps	n/a

How to encode files

Choosing a resolution

MPEG-1 and MPEG-2 video is encoded using blocks of 16x16 pixels but the display dimensions can be anything which is a multiple of 2x2 pixels. The following table shows the LCD sizes of the various Rockbox players supported by mpegplayer, their LCD size, and the suggested resolution for approximate full-screen 4:3 and 16:9 video files.

Players	LCD Size	4:3 Video	16:9 Video
ipod Video & Gigabeat	320x240	320x240	320x180
iriver H300, ipod Color/Photo & Sansa e200	220x176	220x166	220x124
ipod Nano	176x132	176x128	176x100
iaudio X5 / M5 and iriver H10 20GB / H120	160x128	160x120	160x90
ipod Mini 1G / 2G	138x110	138x104	138x78
iriver H10 5/6GB	128x128	128x96	128x72
Sansa c200	132x80	106x80	132x74

Note: Rockbox automatically rotates videos on the Gigabeat to landscape 320x240 and on the Sansa e200 to 220x176.

Encoding

Using WinFF (Windows/Linux)

1) Download and install WinFF 0.29 here: http://biggmatt.com/winff/downloads/winff-version-0.291.html

2) After the program is installed, replace the presets.xml in the WinFF folder (default is C:\Program Files\WinFF\) with this one: presets.xml

3) Run WinFF, pick your desired player from the list, type in any overrides in the boxes at the bottom of the window, add files to the list at the top, and start encoding! Note for Windows Vista users: WinFF may need to be run as an administrator (right click and choose to run it as administrator, or change the properties so that it always does) for it to properly be able to run ffmpeg.

Warning: If you're using the Linux version, and the encoder window flashes and disappears nearly instantly, resulting in 0-size files, it is most likely caused by your build of ffmpeg not having MP3 support. Check the documentation for your Linux distribution and see about compiling or downloading an appropriate replacement.

Using ffmpeg (Linux)

1) Install ffmpeg: on Debian-based systems, "apt-get install ffmpeg" will most likely do the job

2) run ffmpeg

ffmpeg -i [inputfilename] -s [displayresolution] -vcodec mpeg2video -b [video bitrate] -ab [audio bitrate] -ac [audio channels] -ar 44100 -acodec [audio codec] [outputfilename]

Short explanation of the parameters:

Parameter	Info	Good for iPod Photo/Color
-i	filename of the source video	you choose :)
-s	display resolution, f.e. 1024x768	220x166
-vcodec	video codec, must be "mpeg2video"	mpeg2video
-b	video bitrate	200k
-ab	audio bitrate	192k
-ac	audio channels	2
-ar	audio samplerate, must be 44100Hz	44100
-acodec	audio codec, f.e. mp3	mp3 or libmp3lame

The ipod photo/color settings have been tested with some shorter music videos (3-5min) and seemed to work quite well. Framerate stays at about 20fps, minimal frame skipping on fast camera movement visible. The video will be mpeg2-encoded with 192kbps mp3 sound at 44.1KHz and 2 Channels (Stereo). The video bitrate is 200kbps, increasing it will make mpegplayer skip (too) many frames. The resolution of 220x176 will fill the ipod's whole display, except black borders caused by a different aspect ratio in the source video file.

Using VLC to encode on Linux / Mac OS X / Windows

Open a command line prompt and go to the VLC installation directory (default is C:\Program Files\VideoLAN\VLC\ ). Run the following command line:

vlc <input> --sout=#transcode{vcodec=mp2v,vb=600,width=<the width>,height=<the height>,
acodec=mp3,ab=128,samplerate=44100,audio-sync}:std{access=file,mux=ps,url=<filename>.mpg}

Note: You'll need to add quotes around #transcode{....}:std{...} on Linux or OS X.

vb stands for "video bitrate in kbits/sec". 600 kbits/sec should be good enough for most targets ... you might want to try a lower value for small screens.

ab stands for "audio bitrate in kbits/sec" and samplerate is the audio samplerate in Hz. Currently (2nd January 2007), mpegplayer only supports 44.1KHz audio.

Important: mpeg2 allows only some very specific framerates. If encoding fails, it's likely that your source framerate doesn't comply. To change the frame rate, add fps=25 or fps=29.97 in transcode{...}. (This applies to the following .bat file too)

A convenient way for Windows users to achieve the same result is to use VLC-transcode.bat. Simply save this file somewhere and drag&drop a video onto it and it will be transcoded using the above settings. You will probably want to edit the file to change width and height (default is 320x240).

Using Mplayer/Mencoder to encode on Linux / Mac OS X / Windows

MEncoder uses the following command line format:

mencoder <input> <options> -o <output file>

Video options:

-ovc lavc  [output video module]
-lavcoptc vcodec=mpeg2video [output video codec]
...vmax_b_frames=16:vb_strategy=2 [the player needs as many b-frames as possible, to ease decoding and frame skipping]
(note: specify the video bitrate with: mpeg2video:vbitrate=<bitrate>)
-vf scale,harddup [scale the video, remove duplicate frames]
-ofps <fps> [output frames per second, depending on the target, adjust as needed]
-zoom [when scaling, zoom rather than crop]

Audio options:

-oac lavc [output audio module]
-lavcopts acodec=mp3:abitrate=192 [output audio codec and bitrate, mp1/mp2/mp3 can be used]
(note: if your video already has a compatible audio track simply use '-oac copy' to copy it to the output file without transcoding)
-af resample=44100:0:0 [resample to 44.1 kHz, otherwise it won't play at proper speed]

Example

In a terminal do :

mencoder <input> -of mpeg -oac lavc -lavcopts acodec=mp2:abitrate=96:vmax_b_frames=16:vb_strategy=2 -af resample=44100:0:0 -ovc lavc -lavcopts 
vcodec=mpeg2video:vbitrate=<bitrate> -vf scale=<width>:<height>,harddup -ofps 25 -o <filename>.mpg

Other useful options : -ss start position in the input ( -ss 1:20:00 ) -endpos lenght of the output ( -endpos 1:00 )

You can use mpeg1video for the vcodec= instead of mpeg2video

The man page of mencoder : http://www.mplayerhq.hu/DOCS/man/en/mplayer.1.html

Here is an example BAT file for encoding files in Windows with Drag and Drop. The new .mpg file will be made in the same folder as the .bat file (you can even leave the bat on your PMP). Change the settings to your liking(the path to mencoder), I am using these settings on a Gigabeat F.

• encode.bat: Example BAT file for encoding files with mencoder

Using MediaCoder to encode on Windows

MediaCoder offers a point&click alternative to encoding single files, folders or DVD/CD.

1) Download the latest version from their website and install, also download this .zip and unzip it to C:\Program Files\MediaCoder\extensions\

2) Restart MediaCoder, add any files you want to encode (the GUI is very straight forward and their site is helpful if you have any problems) and click the "Extension" button at the top.

3) A pop-up window will give show you list of different devices, click "Rockbox Jukebox" under "Digital Media Player" This will open the Rockbox extension.

4) Here you can select your player and aspect ratio from the drop-down list. (some are grouped together, having the same screen dimensions)

5) Select your preferences and click "Play" to start/stop a preview, Click "Start" to begin the encoding. ("Preview" is to preview the encoded file after the encoding has begun)

6) For more advanced options, return to the main MediaCoder window and adjust the additional settings before starting. (you can also use the "Start" button in the main window)

[To be completed: using mpeg2enc, ...]

Future Development (notes for developers)

Links

• White paper discussing hardware optimisation of libmpeg2 - http://www.quicklogic.com/images/Optimizing_Embedded_Systems_WP.pdf
• Paper: Improving Resource Utilization for MPEG Decoding in Embedded End-Devices - http://crpit.com/confpapers/CRPITV26Ditze.pdf
• Patch with ARM optimisations for an older version (0.3.1) of libmpeg2 - http://boundarydevices.com/archives/mpeg2dec-0.3.1.patch
• A patch to mplayer to skip decoding of frames when using libmpeg2 - http://lists.mplayerhq.hu/pipermail/mplayer-cvslog/2003-April/014603.html
• IDCT from mathematical form to implementable form - http://rnvs.informatik.tu-chemnitz.de/~jan/MPEG/HTML/IDCT.html
• C IDCT optimisation plus MIPS assembly implementation - http://forums.nekochan.net/viewtopic.php?t=2976
• IDCT optimisation paper http://etd.fcla.edu/UF/UFE0000534/gheewala_a.pdf
• MPEG video compression technique explained http://rnvs.informatik.tu-chemnitz.de/~jan/MPEG/HTML/mpeg_tech.html
• Contains DCT implementations by Charilaos Christopoulos of various algorithms http://www.jjj.de/fft/

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CategoryPlugin: MPEG video player [H100, H300, H10, iPod 4G, iPod Color, iPod Mini, iPod Nano, iPod Video, iAudio M5, iAudio X5, Gigabeat, Sansa e200, Sansa c200]