Basic knowledge of Blu-ray encoding
The Blu-ray defines wide-ranging standards to maintain compatibility of playback. This tips explains standards supported by the Accelcoder X along with technical information related to encoding in the Blu-ray.
1. Codecs
Video codec
The Express Authoring feature of Accelcoder X outputs BDMV (Blu-ray Disc Movie) format files. The BDMV format adopts following video codecs. Accelcoder X supports the MPEG-4 AVC/H.264 for 2D and the MPEG-4 MVC for 3D.
- MPEG-2
- MPEG-4 AVC/H.264
- MPEG-4 MVC (3D)
- VC-1
Audio codec
The BDMV format adopts following audio codecs (Optional codecs are excluded). Accelcoder X supports Stereo (2ch), 48kHz, 16bit/sample Linear PCM. Linear PCM is uncompressed audio data (.wav) and has been used in CD. Please note that LPCM for CD cannot be imported directly because the sampling rate is 44.1kHz.
| Codec | Sample frequency | Bit/sample | Max. Channel |
|---|---|---|---|
| Linear PCM | 48 kHz, 96 kHz, 192 kHz | 16, 20, 24 | 8ch (Accelcoder X supports only 2ch) |
| Dolby Digital | 48 kHz | 16, 24 | 5.1ch |
| DTS Digital Surround | 48 kHz | 16, 20, 24 | 5.1ch |
2. Resolution and frame rate
BDMV format supports following resolution and frame rate video. Please note that the combination of resolution and frame rate varies in 3D and 2D.
Blu-ray supported combination of resolution and frame rate
Accelcoder X accepts all combinations.
| Resolution | Frame rate | |
|---|---|---|
| Width | Height | |
| 1920, 1440 | 1080 | 23.976p, 24p, 59.94i, 50i |
| 1280 | 720 | 23.976p, 24p, 59.94p, 50p |
| 720 | 480 | 59.94i |
| 576 | 50i | |
Blu-ray 3D supported combination of resolution and frame rate
Accelcoder X accepts 1920x1080/23.976p and 1280x720/59.94p.
| Resolution | Frame rate | |
|---|---|---|
| Width | Height | |
| 1920 | 1080 | 23.976p |
| 1280 | 720 | 59.94p, 50p |
On the Accelcoder X, frame rate can be converted respectively from 60i/60p/30p/24p to 59.94i/59.94p/29.97p/23.976p at the time of encoding.
3. Bit rate
The maximum video bit rate allowed for Blu-ray is 40 Mbps for 2D, 64Mbps for 3D.
Accelcoder X offers preset templates that include appropriate bit rate, QP value, GOP size, slice count, and other parameters. The maximum bit rate in the preset template is set lower than that of the Blu-ray standard in consideration of decoding performance of Blu-ray players on the market.
The maximum video bit rate of Blu-ray 3D video is only for Base stream. The bit rate of Dependent stream will be set 50% of the Base stream automatically.
