在上一篇的学习中发现，android在设定录音的编码时需要同时设置录音的输出格式，当时不知道怎样的编码对着怎样的格式，最近在看sdk时发现了一点
Table 1. Core media format and codec support.
| Type | Format / Codec | Encoder | Decoder | Details | Supported File Type(s) / Container Formats |
|---|---|---|---|---|---|
| Audio | AAC LC/LTP | • | • | Mono/Stereo content in any combination of standard bit rates up to 160 kbps and sampling rates from 8 to 48kHz | • 3GPP (.3gp) • MPEG-4 (.mp4, .m4a) • ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported) • MPEG-TS (.ts, not seekable, Android 3.0+) |
| HE-AACv1 (AAC+) | • | ||||
| HE-AACv2 (enhanced AAC+) | • | ||||
| AMR-NB | • | • | 4.75 to 12.2 kbps sampled @ 8kHz | 3GPP (.3gp) | |
| AMR-WB | • | • | 9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz | 3GPP (.3gp) | |
| FLAC | •(Android 3.1+) | Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 kHz is recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz downsampler does not include a low-pass filter). 16-bit recommended; no dither applied for 24-bit. | FLAC (.flac) only | ||
| MP3 | • | Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR) | MP3 (.mp3) | ||
| MIDI | • | MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for ringtone formats RTTTL/RTX, OTA, and iMelody | • Type 0 and 1 (.mid, .xmf, .mxmf) • RTTTL/RTX (.rtttl, .rtx) • OTA (.ota) • iMelody (.imy) | ||
| Vorbis | • | • Ogg (.ogg) • Matroska (.mkv, Android 4.0+) | |||
| PCM/WAVE | • | 8- and 16-bit linear PCM (rates up to limit of hardware) | WAVE (.wav) | ||
| Image | JPEG | • | • | Base+progressive | JPEG (.jpg) |
| GIF | • | GIF (.gif) | |||
| PNG | • | • | PNG (.png) | ||
| BMP | • | BMP (.bmp) | |||
| WEBP | •(Android 4.0+) | •(Android 4.0+) | WebP (.webp) | ||
| Video | H.263 | • | • | • 3GPP (.3gp) • MPEG-4 (.mp4) | |
| H.264 AVC | •(Android 3.0+) | • | Baseline Profile (BP) | • 3GPP (.3gp) • MPEG-4 (.mp4) • MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+) | |
| MPEG-4 SP | • | 3GPP (.3gp) | |||
| VP8 | •(Android 2.3.3+) | Streamable only in Android 4.0 and above | • (.webm) • Matroska (.mkv, Android 4.0+) |
Video Encoding Recommendations
Table 2, below, lists examples of video encoding profiles and parameters that the Android media framework supports for playback. In addition to these encoding parameter recommendations, a device's availablevideo recording profiles can be used as a proxy for media playback capabilities. These profiles can be inspected using the class, which is available since API level 8.
Table 2. Examples of supported video encoding parameters.
| SD (Low quality) | SD (High quality) | HD (Not available on all devices) | |
|---|---|---|---|
| Video codec | H.264 Baseline Profile | H.264 Baseline Profile | H.264 Baseline Profile |
| Video resolution | 176 x 144 px | 480 x 360 px | 1280 x 720 px |
| Video frame rate | 12 fps | 30 fps | 30 fps |
| Video bitrate | 56 Kbps | 500 Kbps | 2 Mbps |
| Audio codec | AAC-LC | AAC-LC | AAC-LC |
| Audio channels | 1 (mono) | 2 (stereo) | 2 (stereo) |
| Audio bitrate | 24 Kbps | 128 Kbps | 192 Kbps |
For video content that is streamed over HTTP or RTSP, there are additional requirements: