Large File Playback Issues with Rapsody N35
Various people report about problems with playback of large video files when using the N35's PC network functions based on the smb/cifs protocol. As Rapsody/Dacos is not stating what cifs/smb client implementation they use, I did some brief analysis of the messages the N35 is sending to the smb/cifs server in order to get video data over the network.
The smb/cifs client implementation of the N35 (FW 1.26) has a hard limit at 4GB
When you set your linux samba server to debug level 5, you can see that the N35 is requesting data from the server by SMBread messages. The documentation of Microsoft for the smb/cifs protocol (http://www.jalix.org/ressources/reseaux/nfs-samba/samba/~smb/SMBPUB.DOC) explains the parameters of the read message as follows:

READ: Read File

The read message is sent to read bytes of a resource indicated by Fid in the SMB header. Client Request UCHAR WordCount; USHORT Fid; USHORT Count; ULONG Offset; USHORT Remaining; USHORT ByteCount; Description Count of parameter words = 5 File handle Count of bytes being requested Offset in file of first byte to read Estimate of bytes to read if nonzero Count of data bytes = 0
Count is used to specify the requested number of bytes. Offset specifies the offset in the file of the first byte to be read. Note that this offset is limited to 32 bits, so this client request is inappropriate for files having 64 bit offsets.
In the next step I did an analysis what kind of messages my windows xp machine is sending to the samba server when starting playback with windows media player. This time the reads were done by means of SMBreadX messages. This type of messages is explained in the documentation as follows:

READ_ANDX: Read Data

Client Request UCHAR WordCount; UCHAR AndXCommand; UCHAR AndXReserved; USHORT AndXOffset; USHORT Fid; ULONG Offset; USHORT MaxCount; USHORT MinCount; ULONG Reserved; USHORT Remaining; USHORT ByteCount; Large File Client Request UCHAR WordCount; UCHAR AndXCommand; UCHAR AndXReserved; USHORT AndXOffset; USHORT Fid; ULONG Offset; USHORT MaxCount; USHORT MinCount; ULONG Reserved; USHORT Remaining; ULONG OffsetHigh; USHORT ByteCount; Server Response UCHAR WordCount; UCHAR AndXCommand; UCHAR AndXReserved; USHORT AndXOffset; USHORT Remaining; USHORT DataCompactionMode; USHORT Reserved; USHORT DataLength; USHORT DataOffset; USHORT Reserved[5]; USHORT ByteCount; UCHAR Pad[]; UCHAR Data[ DataLength]; Description Count of parameter words = 10 Secondary (X) command; 0xFF = none Reserved (must be 0) Offset to next command WordCount File handle Offset in file to begin read Max number of bytes to return Min number of bytes to return Must be 0 Bytes remaining to satisfy request Count of data bytes = 0 Description Count of parameter words = 12 Secondary (X) command; 0xFF = none Reserved (must be 0) Offset to next command WordCount File handle Offset in file to begin read Max number of bytes to return Min number of bytes to return Must be 0 Bytes remaining to satisfy request Upper 32 bits of offset Count of data bytes = 0 Description Count of parameter words = 12 Secondary (X) command; 0xFF = none Reserved (must be 0) Offset to next command WordCount Bytes remaining to be read Reserved (must be 0) Number of data bytes (min = 0) Offset (from header start) to data Reserved (must be 0) Count of data bytes Data from resource
If the negotiated dialect is NT LM 0.12 or later, the client may use the Large File version of the request. This version allows specification of 64 bit file offsets. MinCount in the request is valid only if Fid refers to a named pipe. MinCount informs the server that at least MinCount bytes should be returned, if possible.
Instead of the N35's read messages this does support large files with a length above 2^32 (967 296) bytes = 4GB. Now it is clear that the current smb/cifs implementation of the N35 cannot address data in files beyond the 4GB mark. As a result, playback of.iso files (which in case of uncompressed dvd rips have a lot more than 4 GB) is not fully supported. During playback of such a file over smb/cifs by the N35 you will see that playback of chapters beyond the 4GB mark is aborted and the player returns to the main menu of the dvd.

Avis beyond 2GB cannot be played over smb/cifs
While.iso files only seem to be impacted by the hard 4GB limitation and do not show any problem with sizes between 2GB and 4GB, avis and mpgs do have additional problems. Any avi file with more than 2^31 (483 648) Bytes = 2GB will not be played by the N35. The N35 throws an error message, that this file format is not supported. At first, this message puzzles me. This very much indicates that the N35 avi playback software might unfortunately make use of signed integers for file positioning instead of unsigned integers and therefore the smb/cifs client limit of 4GB comes down to the 2GB mark. Taking a wrap around at the 2GB mark into account it is quite obvious that the N35 doesn't get the expected data, but some data from the beginning of the file. This might explain why the error messages says file format not supported. As the N35 seems always to take a look at the end of the file before starting playback, the N35 aborts when you try to playback avis greater Bytes (2GB).
Mpegs beyond 2GB partly work, Mpegs beyond 4GB don't work
The issues with mpegs are a bit more complicated. First of all, it looks like the N35 reads mpegs just from the beginning and doesn't look at the file end. Therefore, mpeg playback always starts ok. On any mpeg larger 2GB a press of the info button on the remote doesn't display the correct file size (it is always 1.0 KB) and it doesn't give any information about the duration of the video. What bothers me more than this hick-up on the info page is that the goto function on the remote is not working. You cannot enter a value there, the file end time stamp is displayed as --:--:--. As a result, the navigation in the mpeg is limited to fast forward and rewind. No jumps at all. Like the avi bug in the previous chapter this looks very much like a bug in the software where signed integers are used for some kinds of file positioning. However, at least you can playback mpegs larger >2GB as long as you just let them run through. I made a test with am mpeg larger 4GB. Here the info page shows a file size of just a few hundred MB and duration of just a few minutes. Looks like a wrap around at 4GB so that the N35 thinks the video is not that long. Playback starts ok, but aborts after having passed the wrong calculated end time of the video.

Closing Thoughts

I think I proved that the smb/cifs client implementation of the N35 does not handle large files >4GB. What adds to this limitation is that avis and mpegs seem to suffer from a signed/unsigned integer problem in the sw layers above the csmb/cifs client. I hope the development team is able to address both problems in the near future. As a first step, it would be nice if Rapsody/Dacos would confirm these bugs. If anyone has different findings, please let me know (n35 at pasternak.net). As I far as we cannot look into the sources it is always partly guesswork what exactly goes wrong. but this is another story.

19.09.2007 RAPSODY N35 Firmware Version 3.04 beta Baboda 1. add support to access shared folder under Windows Vista 2. add support to show high resolution JPEG files 3. improve AVI play function and response 4. improve video.ts &.tp play at 1080p resolution 5. improve HDD and USB mount and recognition speed 6. improve DVD menu cursor focus 7. bug fix for audio/video sync for certain AVI files 8. bug fix for volume display 9. bug fix to correct location focus for HOME function 10. allow folders to be sorted 11. bug fix for USB indicator 12. add support for WIFI access via USB 802.11a/b/g adaptor (soon) 13. changed autoplay function 14. PLAYLIST function on the remote and mainmenu has been disabled to support Internet Radio Station Access (soon) 15. miscellaneous bug fix and improvements Este firmware ha sido desarrollado por la empresa Daboda que ha liberado el firmware y ha introducido mejoras, algunas de ellas disponibles prximamente como conectividad Wi-Fi por USB y soporte para internet Radio. El firmware para los modelos Daboda HMC1 y N35 es el mismo, ya que son modelos idnticos.
16.08.2007 RAPSODY N35 Firmware Version 3.02 1. The response speed of AVI files playback has Improved three~four times than before. 2. Improved the HD JPEG image quality. 3. Improved the OSD/MessageBox and fixed some bugs. 4. Supported LED On/Off when USB is connected & disconnected. 5. Fixed MP3 Navigation bugs. 6. Fixed the others bugs.
10.04.2007 RAPSODY N35 Firmware Version 1.26 * Korean, English, Spanish, Russian, French, German, Czech.
1. Fixed a bug that some ID3 tags (v1) were not shown. 2. Added support for displaying ID3v2 tags (basic information only). 3. Fixed a bug that MP3 files with included cover art (image in ID3v2 tag) over a specific size (~100 kb) could not be played. 4. FINALLY: Added support for OGG Vorbis audio playback! 5. Added support for czech language. 6. Added the function, that it will automatically play the content of a Video_TS folder when you press play on it. 7. Improved HD video playback / 1080p support. Supports fluid playing and FF of WMV-HD files in 1080p resolution. Also works better with DivX-HD, but still has some problems here with 1080p files (freezes). We're working on this. 8. Enhanced playback of MPEG *HD* files, it's not perfect yet (development still in progress, FF doesn't really work) but it's already better than in our last firmware release. Please also read the note below! Note: For some MPEG HD files our "experimental beta" 1.25-b2 (N35 only) will work much better, but contains several bugs. For users which need best possible MPEG2 HD playback right now (anyway still no working FF here), this might be a temporary solution. Of course we'll have this completely fixed in next version. Anyway it needs some more time, so we didn't want to hold back version 1.26 just because of this. 9. Fixed that video settings in setup menu did show wrong information.

30.01.2007 RAPSODY N35 Firmware Version 1.20 * Korean, English, Spanish, Russian, French, German 1. Added play and pause function for photo slide show, just press the OK button. Also it's possible now to change the slide show duration during playback by pressing the SYNC button +/-. 2. Added support for the "srt" subtitle format. 3. Enhanced support for two audio streams (3 seconds to switch) 4. Fixed a display problem with russian file names.
22.01.2007 RAPSODY N35 Firmware Version 1.19 * Korean, English, Spanish, Russian, French, German 1. Adding the Play and Pause function while it is being JPEG Shlide Show. Press the "OK" button. 2. Supporting the "srt" Subtitles. 3. Supporting Two Audio Function(interval 3 seconds) 4. Fixed the Language Problem, ex)Russia Language's file name.
* Using of "SYNC" Button of Remote. If you press this button, you can control the time "up and down" when it is being slide show of JPEG.
10.01.2007 RAPSODY N35 Firmware Version 1.18 * Korean, English, Spanish, Russian, French, German * 1. USB Host Play connecting to USB Host Port of N35. The compatible ODD models are below, - Maker : LG Model No : GSA-E10N Product Name : External Super Multi DVD Rewriter. - Maker : HP Model No : dvd840e Product Name : Super Multi DVD Writer. ---> It could be compatilbe to Version-Up Model in case of Same Model No. ---> In case of not open the tray(DVD) while playing. please select "refresh" in the screen or go out from USB Disk Selection. 2. Fixed incorrect of PAL Screen in Set-up(300). 3. Fixed showing blank HDD symptom when selecting the Russian Language.
10.12.2006 RAPSODY N35 Firmware Version 1.17 * Korean, English, Spanish, Russian, French, German * 1. USB Host Play connecting to USB Host Port of N35. The compatible ODD models are below, - Maker : LG Model No : GSA-E10N Product Name : External Super Multi DVD Rewriter. - Maker : HP Model No : dvd840e Product Name : Super Multi DVD Writer. ---> Could be compatilbe a Version-Up Model in the Same Model. ---> Not open the tray(DVD) while playing. At this time, please select "refresh". 2. Fixed incorrect of PAL Screen in Set-up(300). 3. Fixed showing blank HDD symptom when selecting the Russian Language.

10.11.2006 RAPSODY N35 Firmware Version 1.15 * Korean, English, Spanish, Russian, French, German * 1. Fixed some bugs. 2. Added playlist function. Please refer to the following. 3. Added DVD audio selection. 4. Added Subtitile selection. 5. Added two audion selection(change interval timing : 13~14 seconds) Playlist function : <Functions> 1. Creat a Folder as name "playlist" to the disk1. 2. Copy some music files into the "playlist" folder.
3. When you selecting the "Playlist" in Menu of N35, or pressing "Playlist" button on remote, it will be auto-start. 4. Advantage : You can listen to music without the monitor.
13.10.2006 RAPSODY N35 Firmware Version 1.14 * Korean, English, Spanish, Russian, French, German * 1. Fixed some bugs. 2. Added playlist function. Please refer to the following. Playlist function : <Functions> 1. Creating Folder named "playlist" in disk1. 2. Copy the music files that you'd like to play automatically. 3. When you select the "Playlist" in Menu of N35, it will be automatically played in order. 4. It is the same when you press the button "Playlist" on remote. 5. Advantage : You can automatically listen to music without some monitor as just pressing the Playlist Button on remote.
10.09.2006 RAPSODY N35 Firmware Version 1.13 * Korean, English, Spanish, Russian, French, German * <Change List> 1. Possible to change DVD Audio. 2. Possible to change DVD Subtitle. 3. Fixed Sync discord. 4. Re-arranged Subtitle position. 5. Re-fixed the Screen Ratio.
15.08.2006 RAPSODY N35 Firmware Version 1.12 * Korean, English, Spanish, Russian, French, German * 1. Fixed the screen ratio problem (letter box, pan/scan, 16:9) 2. Decreased the file buffering. 3. Fixed 16/32 forward problem, it's the Buffer!