@@ -32,8 +32,8 @@ static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out)
uint32_t header;
int sample_rate= ctx->par_in->sample_rate;
int sample_rate_index=0;
- int lsf, mpeg25, bitrate_index, frame_size, ret;
- uint8_t *buf;
+ int lsf, mpeg25, bitrate_index, frame_size, offset, ret;
+ const uint8_t *buf;
int buf_size;
ret = ff_bsf_get_packet(ctx, &in);
@@ -69,23 +69,25 @@ static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out)
sample_rate= avpriv_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25); //in case sample rate is a little off
- for(bitrate_index=2; bitrate_index<30; bitrate_index++){
- frame_size = avpriv_mpa_bitrate_tab[lsf][2][bitrate_index>>1];
- frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1);
- if(frame_size == buf_size + 4)
- break;
- if(frame_size == buf_size + 6)
+ for (bitrate_index = 1; bitrate_index < 15; bitrate_index++) {
+ frame_size = avpriv_mpa_bitrate_tab[lsf][2][bitrate_index];
+ frame_size = (frame_size * 144000) / (sample_rate << lsf);
+ offset = frame_size - buf_size;
+ if (3 <= offset && offset <= 6)
break;
}
- if(bitrate_index == 30){
+ if (bitrate_index == 15) {
av_log(ctx, AV_LOG_ERROR, "Could not find bitrate_index.\n");
ret = AVERROR(EINVAL);
goto fail;
}
- header |= (bitrate_index&1)<<9;
- header |= (bitrate_index>>1)<<12;
- header |= (frame_size == buf_size + 4)<<16;
+ header |= bitrate_index << 12;
+ if (offset & 1) {
+ header |= 1 << 9; // padding_bit
+ frame_size++;
+ offset++;
+ }
ret = av_new_packet(out, frame_size);
if (ret < 0)
@@ -95,10 +97,10 @@ static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out)
av_packet_unref(out);
goto fail;
}
- memcpy(out->data + frame_size - buf_size, buf, buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
+ memcpy(out->data + offset, buf, buf_size);
if(ctx->par_in->channels==2){
- uint8_t *p= out->data + frame_size - buf_size;
+ uint8_t *p = out->data + offset;
if(lsf){
FFSWAP(int, p[1], p[2]);
header |= (p[1] & 0xC0)>>2;
@@ -109,10 +111,11 @@ static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out)
}
}
- if (frame_size == buf_size + 6) {
+ if (offset == 6) {
//FIXME actually set a correct crc instead of 0
AV_WN16(out->data + 4, 0);
- }
+ } else
+ header |= 1 << 16; // protection_bit
AV_WB32(out->data, header);
ret = 0;
Up until now, the mp3_header_decompress bsf used a single variable for two purposes in a bitfield-like manner: To contain the bitrate index as well as whether the padding_bit is set. The former was contained in bits 1-4, while the latter was given by bit 0. This made the code hard to understand. This commit changes this by using dedicated variables for the bitrate index as well as for the offset of the old data in the new buffer. The latter implicitly contains whether the padding_bit is set. Also add const to the pointer to the source data; it is of course not modified. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> --- libavcodec/mp3_header_decompress_bsf.c | 35 ++++++++++++++------------ 1 file changed, 19 insertions(+), 16 deletions(-)