oysteikt
/
mpd
0
0
Fork 0
Code Issues Pull Requests Releases Activity

decoder/ffmpeg: align the output buffer 

On some platforms, libavcodec wants the output buffer aligned to 16
bytes (because it uses SSE/Altivec internally).  It will segfault when
you don't obey this rule.
This commit is contained in:
Max Kellermann 2009-11-15 17:39:09 +01:00
parent dca4d9cf83
commit 77b95d08a5
2 changed files with 25 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
NEWS
View File

@ -6,6 +6,7 @@ ver 0.15.6 (2009/??/??)
- zzip: require libzzip 0.13 - zzip: require libzzip 0.13
* decoders: * decoders:
- ffmpeg: convert metadata - ffmpeg: convert metadata
- ffmpeg: align the output buffer
- oggflac: rewind stream after FLAC detection - oggflac: rewind stream after FLAC detection
- flac: fixed CUE seeking range check - flac: fixed CUE seeking range check
* output_thread: check again if output is open on PAUSE * output_thread: check again if output is open on PAUSE

29
src/decoder/ffmpeg_plugin.c
View File

@ -209,6 +209,21 @@ ffmpeg_helper(struct input_stream *input,
return ret; return ret;
} }
/**
* On some platforms, libavcodec wants the output buffer aligned to 16
* bytes (because it uses SSE/Altivec internally). This function
* returns the aligned version of the specified buffer, and corrects
* the buffer size.
*/
static void *
align16(void *p, size_t *length_p)
{
unsigned add = 16 - (size_t)p % 16;
*length_p -= add;
return (char *)p + add;
}
static enum decoder_command static enum decoder_command
ffmpeg_send_packet(struct decoder *decoder, struct input_stream *is, ffmpeg_send_packet(struct decoder *decoder, struct input_stream *is,
const AVPacket *packet, const AVPacket *packet,
@ -217,7 +232,9 @@ ffmpeg_send_packet(struct decoder *decoder, struct input_stream *is,
{ {
enum decoder_command cmd = DECODE_COMMAND_NONE; enum decoder_command cmd = DECODE_COMMAND_NONE;
int position; int position;
uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2]; uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2 + 16];
int16_t *aligned_buffer;
size_t buffer_size;
int len, audio_size; int len, audio_size;
uint8_t *packet_data; uint8_t *packet_data;
int packet_size; int packet_size;
@ -225,11 +242,13 @@ ffmpeg_send_packet(struct decoder *decoder, struct input_stream *is,
packet_data = packet->data; packet_data = packet->data;
packet_size = packet->size; packet_size = packet->size;
buffer_size = sizeof(audio_buf);
aligned_buffer = align16(audio_buf, &buffer_size);
while ((packet_size > 0) && (cmd == DECODE_COMMAND_NONE)) { while ((packet_size > 0) && (cmd == DECODE_COMMAND_NONE)) {
audio_size = sizeof(audio_buf); audio_size = buffer_size;
len = avcodec_decode_audio2(codec_context, len = avcodec_decode_audio2(codec_context,
(int16_t *)audio_buf, aligned_buffer, &audio_size,
&audio_size,
packet_data, packet_size); packet_data, packet_size);
if (len < 0) { if (len < 0) {
@ -250,7 +269,7 @@ ffmpeg_send_packet(struct decoder *decoder, struct input_stream *is,
: 0; : 0;
cmd = decoder_data(decoder, is, cmd = decoder_data(decoder, is,
audio_buf, audio_size, aligned_buffer, audio_size,
position, position,
codec_context->bit_rate / 1000, NULL); codec_context->bit_rate / 1000, NULL);
} }