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avcodec/libmp3lame: add ABR support 

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Timothy Gu 2013-11-01 19:43:24 -07:00 committed by Michael Niedermayer
parent 67d1d06225
commit d3211cfaed
2 changed files with 15 additions and 3 deletions
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7
doc/encoders.texi
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@ -785,7 +785,7 @@ The following options are supported by the libmp3lame wrapper. The
@table @option
@item b (@emph{-b})
Set bitrate expressed in bits/s for CBR. LAME @code{bitrate} is
Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
expressed in kilobits/s.
@item q (@emph{-V})
@ -807,6 +807,11 @@ has this enabled by default, but can be overriden by use
Enable the encoder to use (on a frame by frame basis) either L/R
stereo or mid/side stereo. Default value is 1.
@item abr (@emph{--abr})
Enable the encoder to use ABR when set to 1. The @command{lame}
@option{--abr} sets the target bitrate, while this options only
tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
@end table
@section libopencore-amrnb

11
libavcodec/libmp3lame.c
View File

@ -49,6 +49,7 @@ typedef struct LAMEContext {
int buffer_size;
int reservoir;
int joint_stereo;
int abr;
float *samples_flt[2];
AudioFrameQueue afq;
AVFloatDSPContext fdsp;
@ -119,8 +120,13 @@ static av_cold int mp3lame_encode_init(AVCodecContext *avctx)
lame_set_VBR(s->gfp, vbr_default);
lame_set_VBR_quality(s->gfp, avctx->global_quality / (float)FF_QP2LAMBDA);
} else {
if (avctx->bit_rate) // CBR
lame_set_brate(s->gfp, avctx->bit_rate / 1000);
if (avctx->bit_rate) {
if (s->abr) { // ABR
lame_set_VBR(s->gfp, vbr_abr);
lame_set_VBR_mean_bitrate_kbps(s->gfp, avctx->bit_rate / 1000);
} else // CBR
lame_set_brate(s->gfp, avctx->bit_rate / 1000);
}
}
/* do not get a Xing VBR header frame from LAME */
@ -265,6 +271,7 @@ static int mp3lame_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
static const AVOption options[] = {
{ "reservoir", "use bit reservoir", OFFSET(reservoir), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, AE },
{ "joint_stereo", "use joint stereo", OFFSET(joint_stereo), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, AE },
{ "abr", "use ABR", OFFSET(abr), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AE },
{ NULL },
};