FFmpeg: libavcodec/gsm_parser.c Source File

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libavcodec

gsm_parser.c

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1 /*

3 *

4 * This file is part of Libav.

5 *

6 * Libav is free software; you can redistribute it and/or

7 * modify it under the terms of the GNU Lesser General Public

8 * License as published by the Free Software Foundation; either

9 * version 2.1 of the License, or (at your option) any later version.

10 *

11 * Libav is distributed in the hope that it will be useful,

12 * but WITHOUT ANY WARRANTY; without even the implied warranty of

13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

14 * Lesser General Public License for more details.

15 *

16 * You should have received a copy of the GNU Lesser General Public

17 * License along with Libav; if not, write to the Free Software

18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

19 */

21 /**

22 * @file

23 * GSM audio parser

24 *

25 * Splits packets into individual blocks.

26 */

28 #include "parser.h"

29 #include "gsm.h"

31 typedef struct GSMParseContext {

32 ParseContext pc;

33 int block_size;

34 int duration;

35 int remaining;

36 } GSMParseContext;

38 static int gsm_parse(AVCodecParserContext *s1, AVCodecContext *avctx,

39 const uint8_t **poutbuf, int *poutbuf_size,

40 const uint8_t *buf, int buf_size)

41 {

42 GSMParseContext *s = s1->priv_data;

43 ParseContext *pc = &s->pc;

44 int next;

46 if (!s->block_size) {

47 switch (avctx->codec_id) {

48 case AV_CODEC_ID_GSM:

49 s->block_size = GSM_BLOCK_SIZE;

50 s->duration = GSM_FRAME_SIZE;

51 break;

52 case AV_CODEC_ID_GSM_MS:

53 s->block_size = GSM_MS_BLOCK_SIZE;

54 s->duration = GSM_FRAME_SIZE * 2;

55 break;

56 default:

57 *poutbuf = buf;

58 *poutbuf_size = buf_size;

59 av_log(avctx, AV_LOG_ERROR, "Invalid codec_id\n");

60 return buf_size;

61 }

62 }

64 if (!s->remaining)

65 s->remaining = s->block_size;

66 if (s->remaining <= buf_size) {

67 next = s->remaining;

68 s->remaining = 0;

69 } else {

70 next = END_NOT_FOUND;

71 s->remaining -= buf_size;

72 }

74 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {

75 *poutbuf = NULL;

76 *poutbuf_size = 0;

77 return buf_size;

78 }

80 s1->duration = s->duration;

82 *poutbuf = buf;

83 *poutbuf_size = buf_size;

84 return next;

85 }

87 AVCodecParser ff_gsm_parser = {

88 .codec_ids = { AV_CODEC_ID_GSM, AV_CODEC_ID_GSM_MS },

89 .priv_data_size = sizeof(GSMParseContext),

90 .parser_parse = gsm_parse,

91 .parser_close = ff_parse_close,

92 };

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