On 2/9/2017 2:40 PM, Alex Converse wrote: > diff --git a/libavcodec/mpeg4audio.c b/libavcodec/mpeg4audio.c > index 5f85b64cb8..9fe257838c 100644 > --- a/libavcodec/mpeg4audio.c > +++ b/libavcodec/mpeg4audio.c > @@ -83,70 +83,62 @@ static inline int get_sample_rate(GetBitContext *gb, int > *index) > avpriv_mpeg4audio_sample_rates[*index]; > } > > -int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, > - int bit_size, int sync_extension) > +int avpriv_mpeg4audio_get_config_gb(MPEG4AudioConfig *c, GetBitContext *gb, > + int sync_extension)
Please, keep this new function internal (ff_ prefix) until it's actually needed by libavformat. > { > - GetBitContext gb; > int specific_config_bitindex, ret; > - > - if (bit_size <= 0) > - return AVERROR_INVALIDDATA; > - > - ret = init_get_bits(&gb, buf, bit_size); > - if (ret < 0) > - return ret; > - > - c->object_type = get_object_type(&gb); > - c->sample_rate = get_sample_rate(&gb, &c->sampling_index); > - c->chan_config = get_bits(&gb, 4); > + int start_bit_index = get_bits_count(gb); > + c->object_type = get_object_type(gb); > + c->sample_rate = get_sample_rate(gb, &c->sampling_index); > + c->chan_config = get_bits(gb, 4); > if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels)) > c->channels = ff_mpeg4audio_channels[c->chan_config]; > c->sbr = -1; > c->ps = -1; > if (c->object_type == AOT_SBR || (c->object_type == AOT_PS && > // check for W6132 Annex YYYY draft MP3onMP4 > - !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) { > + !(show_bits(gb, 3) & 0x03 && !(show_bits(gb, 9) & 0x3F)))) { > if (c->object_type == AOT_PS) > c->ps = 1; > c->ext_object_type = AOT_SBR; > c->sbr = 1; > - c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index); > - c->object_type = get_object_type(&gb); > + c->ext_sample_rate = get_sample_rate(gb, &c->ext_sampling_index); > + c->object_type = get_object_type(gb); > if (c->object_type == AOT_ER_BSAC) > - c->ext_chan_config = get_bits(&gb, 4); > + c->ext_chan_config = get_bits(gb, 4); > } else { > c->ext_object_type = AOT_NULL; > c->ext_sample_rate = 0; > } > - specific_config_bitindex = get_bits_count(&gb); > + specific_config_bitindex = get_bits_count(gb); > > if (c->object_type == AOT_ALS) { > - skip_bits(&gb, 5); > - if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S')) > - skip_bits_long(&gb, 24); > + skip_bits(gb, 5); > + if (show_bits_long(gb, 24) != MKBETAG('\0','A','L','S')) > + skip_bits_long(gb, 24); > > - specific_config_bitindex = get_bits_count(&gb); > + specific_config_bitindex = get_bits_count(gb); > > - ret = parse_config_ALS(&gb, c); > + ret = parse_config_ALS(gb, c); > if (ret < 0) > return ret; > } > > if (c->ext_object_type != AOT_SBR && sync_extension) { > - while (get_bits_left(&gb) > 15) { > - if (show_bits(&gb, 11) == 0x2b7) { // sync extension > - get_bits(&gb, 11); > - c->ext_object_type = get_object_type(&gb); > - if (c->ext_object_type == AOT_SBR && (c->sbr = > get_bits1(&gb)) == 1) { > - c->ext_sample_rate = get_sample_rate(&gb, > &c->ext_sampling_index); > + while (get_bits_left(gb) > 15) { > + if (show_bits(gb, 11) == 0x2b7) { // sync extension > + get_bits(gb, 11); > + c->ext_object_type = get_object_type(gb); > + if (c->ext_object_type == AOT_SBR && (c->sbr = > get_bits1(gb)) == 1) { > + c->ext_sample_rate = get_sample_rate(gb, > &c->ext_sampling_index); > if (c->ext_sample_rate == c->sample_rate) > c->sbr = -1; > } > - if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548) > - c->ps = get_bits1(&gb); > + if (get_bits_left(gb) > 11 && get_bits(gb, 11) == 0x548) > + c->ps = get_bits1(gb); > break; > } else > - get_bits1(&gb); // skip 1 bit > + get_bits1(gb); // skip 1 bit > } > } > > @@ -157,7 +149,23 @@ int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, > const uint8_t *buf, > if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01) > c->ps = 0; > > - return specific_config_bitindex; > + return specific_config_bitindex - start_bit_index; > +} > + > +int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, > + int bit_size, int sync_extension) > +{ > + GetBitContext gb; > + int ret; > + > + if (bit_size <= 0) > + return AVERROR_INVALIDDATA; > + > + ret = init_get_bits(&gb, buf, bit_size); > + if (ret < 0) > + return ret; > + > + return avpriv_mpeg4audio_get_config_gb(c, &gb, sync_extension); > } > > static av_always_inline unsigned int copy_bits(PutBitContext *pb, > diff --git a/libavcodec/mpeg4audio.h b/libavcodec/mpeg4audio.h > index 8239081747..5f362e87e3 100644 > --- a/libavcodec/mpeg4audio.h > +++ b/libavcodec/mpeg4audio.h > @@ -45,7 +45,17 @@ extern av_export const int > avpriv_mpeg4audio_sample_rates[16]; > extern const uint8_t ff_mpeg4audio_channels[8]; > > /** > - * Parse MPEG-4 systems extradata to retrieve audio configuration. > + * Parse MPEG-4 systems extradata from a potentially unaligned GetBitContext > to retrieve audio configuration. > + * @param[in] c MPEG4AudioConfig structure to fill. > + * @param[in] gb Extradata from container. > + * @param[in] sync_extension look for a sync extension after config if true. > + * @return On error -1 is returned, on success AudioSpecificConfig bit index > in extradata. > + */ > +int avpriv_mpeg4audio_get_config_gb(MPEG4AudioConfig *c, GetBitContext *gb, > + int sync_extension); > + > +/** > + * Parse MPEG-4 systems extradata from a raw buffer to retrieve audio > configuration. > * @param[in] c MPEG4AudioConfig structure to fill. > * @param[in] buf Extradata from container. > * @param[in] bit_size Extradata size in bits. > -- 2.11.0.483.g087da7b7c-goog _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel