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faad: optimize channel remap, avoid potential memcpy

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Combine the channel remap and copy in one operation. Calculate the channel remap
table only once, make a shortcut when we are not doing any remapping.
This commit is contained in:
Wim Taymans 2012-03-20 16:34:33 +01:00
parent c7f9558cc4
commit 5ed4e21221
2 changed files with 40 additions and 5 deletions
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43
ext/faad/gstfaad.c
View file

@ -473,14 +473,13 @@ gst_faad_update_caps (GstFaad * faad, faacDecFrameInfo * info)
gboolean ret;
gboolean fmt_change = FALSE;
GstAudioInfo ainfo;
gint i;
/* see if we need to renegotiate */
if (info->samplerate != faad->samplerate ||
info->channels != faad->channels || !faad->channel_positions) {
fmt_change = TRUE;
} else {
gint i;
for (i = 0; i < info->channels; i++) {
if (info->channel_position[i] != faad->channel_positions[i]) {
fmt_change = TRUE;
@ -520,6 +519,19 @@ gst_faad_update_caps (GstFaad * faad, faacDecFrameInfo * info)
if (ainfo.position[0] != GST_AUDIO_CHANNEL_POSITION_NONE)
ainfo.flags &= ~GST_AUDIO_FLAG_UNPOSITIONED;
/* get the remap table */
memset (faad->reorder_map, 0, sizeof (faad->reorder_map));
faad->need_reorder = FALSE;
if (gst_audio_get_channel_reorder_map (faad->channels, faad->aac_positions,
faad->gst_positions, faad->reorder_map)) {
for (i = 0; i < faad->channels; i++) {
if (faad->reorder_map[i] != i) {
faad->need_reorder = TRUE;
break;
}
}
}
ret = gst_audio_decoder_set_output_format (GST_AUDIO_DECODER (faad), &ainfo);
return ret;
@ -720,6 +732,7 @@ init:
info.error = 0;
do {
GstMapInfo map;
if (!faad->packetised) {
/* faad only really parses ADTS header at Init time, not when decoding,
@ -746,6 +759,8 @@ init:
(guint) info.bytesconsumed, (guint) info.samples);
if (out && info.samples > 0) {
guint channels, samples;
if (!gst_faad_update_caps (faad, &info))
goto negotiation_failed;
@ -753,12 +768,30 @@ init:
if (info.samples > G_MAXUINT / faad->bps)
goto sample_overflow;
channels = faad->channels;
/* note: info.samples is total samples, not per channel */
samples = info.samples / channels;
/* FIXME, add bufferpool and allocator support to the base class */
outbuf = gst_buffer_new_allocate (NULL, info.samples * faad->bps, NULL);
gst_buffer_fill (outbuf, 0, out, info.samples * faad->bps);
gst_audio_buffer_reorder_channels (outbuf, GST_AUDIO_FORMAT_S16,
faad->channels, faad->aac_positions, faad->gst_positions);
gst_buffer_map (outbuf, &map, GST_MAP_READWRITE);
if (faad->need_reorder) {
gint16 *dest, *src, i, j;
dest = (gint16 *) map.data;
src = (gint16 *) out;
for (i = 0; i < samples; i++) {
for (j = 0; j < channels; j++) {
dest[faad->reorder_map[j]] = *src++;
}
dest += channels;
}
} else {
memcpy (map.data, out, map.size);
}
gst_buffer_unmap (outbuf, &map);
ret = gst_audio_decoder_finish_frame (dec, outbuf, 1);
}

2
ext/faad/gstfaad.h
View file

@ -50,6 +50,8 @@ typedef struct _GstFaad {
guint bps; /* bytes per sample */
guchar *channel_positions;
GstAudioChannelPosition aac_positions[6], gst_positions[6];
gboolean need_reorder;
gint reorder_map[64];
guint8 fake_codec_data[2];
guint32 last_header;