After hours and hours of analysis and deduction, we come to the decision that External CD/DVD Drive USB 3.0/2.0 Portable High Speed Data Transfer CD/DVD-RW Drive/Writer/Rewriter/Player for MacBook Pro Laptop/Desktops Win 7/8.1/10 and Linux OS by BAGEYI (White) could be the best external dvd players for your needs. See articles on the formats in question for information on compatibility issues.We always take that extra step while reviewing products, so that our user base only gets exposed to the best and reliable external dvd players.
(SL) stands for standard single-layer discs, while DL denotes the dual-layer variants. Recordable DVD capacity comparison įor comparison, the table below shows storage capacities of the four most common DVD recordable media, excluding DVD-RAM. This results in the video skipping or freezing up for some time as the laser head repositions itself and the system waits to start receiving data again. OTP is usually used for DVD-Video, to prevent the inherent delay that PTP involves: in PTP, the laser head moves from the outside edge of the DVD to the inside to start reading L1 when it reaches the end of L0. Since dual-layer DVDs have two data layers, placed one on top of the other – Layer 0 (L0) and Layer 1 (L1), there are two ways in which these two layers may be written to - L0, inside to outside and then L1 inside to outside again (PTP), or L0 inside to outside and then L1 outside to inside (OTP). A simpler way to understand what's written above is to think of the little hole in the centre of the DVD as the "inside" and the rim of the DVD as the "outside". This is to minimize the time that the video player takes to locate and focus on the second layer and thus provide the shortest possible pause in the content as the layer changes.Ī common misconception is that the disc spins first in one direction, and then another, either for PTP or OTP recording, when in fact DVD-Writers always spin a disc in the clockwise direction. This means that the 'start' of the second layer may not have any recorded material present. DVD-Video is always recorded in OTP mode, but the video data is read from the beginning of the first layer towards the end of the first layer, when this ends (not necessarily at the end of the track) then reading is transferred to the second layer, but the video data commences from the same physical location that the first layer ends back towards the beginning of the second layer. In OTP mode, the second layer is read from the outside of the disk.įor DVD-Video a variation of the technique is employed. Sectors are sequenced from the beginning of the first layer to the end of the first layer, then the beginning of the second layer to the end of the second layer. In PTP mode, used for DVD-ROM, both layers start recording at the inside diameter (ID) with the lead-in and end at the outside diameter (OD) with the lead-out. There are two modes for dual-layer orientation, parallel track path (PTP) and opposite track path (OTP). The transfer rates reached by dual-layer media for both reading and recording speeds are still well below those of single-layer media. Many current DVD recorders support dual-layer technology, and the price is now comparable to that of single-layer drives, though the blank media remain more expensive. Studios began listing a standard message explaining this pausing effect on all dual-layer disc packaging.ĭVD recordable discs supporting this technology are backward compatible with some existing DVD players and DVD-ROM drives. This caused some viewers to worry that their dual-layer discs were damaged or defective. The layer change can exhibit a noticeable pause in some DVD players, up to several seconds. The drive with dual-layer capability accesses the second layer by shining the laser through the first semi-transparent layer. Ī dual-layer disc differs from its usual DVD counterpart by employing a second physical layer within the disc itself. DVD-R DL was developed for the DVD Forum by Pioneer Corporation, while DVD+R DL was developed for the DVD+RW Alliance by Philips and Mitsubishi Kagaku Media (MKM). High-Definition Versatile Multilayer Disc (HD VMD)ĭual-layer recording allows DVD-R and DVD+R discs to store significantly more data, up to 8.5 gigabytes per disc, compared with 4.7 gigabytes for single-layer discs.HD DVD: HD DVD-R, HD DVD-RW, HD DVD-RAM.Blu-ray Disc ( BD): BD-R & BD-RE, Blu-ray 3D, Mini Blu-ray Disc.
DVD: DVD-R, DVD+R, DVD-R DL, DVD+R DL, DVD-R DS, DVD+R DS, DVD-RW, DVD+RW, DVD-RAM, DVD-D, DVD-A, HVD, EcoDisc, MiniDVD.Compact disc ( CD): CD-DA, CD-ROM, CD-R, CD-RW, 5.1 Music Disc, Super Audio CD ( SACD), Photo CD, CD Video ( CDV), Video CD ( VCD), Super Video CD ( SVCD), CD+G, CD-Text, CD-ROM XA, CD-i, MIL-CD, Mini CD.